foobuzz

The Principle of Total Evidence

2023-11-17T00:00:00Z

There is a common anecdote which consists in stating the likelihood of dying from a falling coconut, and sometimes comparing it to, say, the likelihood of dying from a shark attack. Those probabilities are usually inferred by taking the number of casualties of those bizarre deaths each year, and dividing it by the number of people on Earth, or something like that.

If I point my index finger to you and state: "You have X% probability of dying from a falling coconut this year", is that accurate? No, because you surely have more information about yourself than the fact that you inhabit Earth. If, for example, you live in Paris and don't go surfing on islands with coconut trees, then the more accurate probability for you is way way closer to zero.

The more I think about this observation, the more I notice examples where it is relevant.

So-called "rationalist" people are often comparing sets of overall probabilities of society without nuance. They say you shouldn't fear terrorism in comparison to car accidents or to common law crimes. But what if I barely ever ride in any car? What if I have no enemy, a healthy relationship, no tie whatsoever to criminal affairs, but that I do go often to events in a big city? Do I really have a higher probability of dying in a common crime than in a terrorist attack? As soon as there is more information than merely "living in France", all your likelihood estimations about what I should fear are potentially worthless.

When interacting with a group of people, racist people will be prone to point out the one they're prejudiced against as the "statistically most likely" to commit some offense, with supporting evidence of statistical records "proving" their point. Except they have conveniently ignored all the other available information. Gender, profession, place of living, socio-professional category, etc, are surely way stronger predictors than whatever dimension they tunneled-vision into, and, if taken into account, could very well direct their attention to someone else in the crowd (maybe themselves).

When I shared this observation with ChatGPT, he directed me to the notions of Bayesian inference, which is a statistical technique used to update some probability when more information becomes available, and to the Principle of Total Evidence, which apparently states that one should include all the information available whenever stating some probability.

I don't have any grand conclusion about this matter, apart from the fact that stating likelihoods is tricky, and you should always try to include as much information as possible when doing so.

The uniqueness of sentences

2023-11-04T00:00:00Z

We tend to underestimate combinatorial explosion.

For example, there is a somewhat famous anecdote which states that if you shuffle a standard deck of cards, then the sequence of cards you hold in your hand is unique in the history of mankind. Indeed, there are 52! ≅ 10^67 sequences possible, which will yield unique combinations with any good enough shuffle.

Another example is the famous XKCD about password strength which noted that sequences of 4 words from a 10,000 words dictionary yields harder passwords than pseudo-complex passwords mixing digits, letters, and special characters out of a single known word.

More recently, the advent of Large Language Models (LLMs) under the spotlight is highlighting the combinatorial nature of text. See, all that LLMs do is predicting the next word that should come after a bunch of words, according to what is usually seen in recorded language.

If that could be done purely statistically, that's how the LLM would do it. For example, if you want to complete the text "the whole nine", then you can make a table of what are the words that historically came after the text "the whole nine" in recorded language, and take the word with the most hits as a safe next word. In this case, that would be "yards", because of the English expression the whole nine yards, whose usage surely overwhelms any other text starting with "the whole nine".

The problem is that this method of looking up the statistics only works with very small sequences of words or very idiomatic expressions. With anything a bit more complex, there is no statistics at all, for the simple reason that the sequence of words has never been written or said before. This is what the "model" does in the LLM: it is trained on a large collection of inputs and associated outputs (sequences of words, and for each one of them the words that come next most of the time), and then is able to make a prediction about an input it has never seen before. That is the very nature of neural networks.

In the case of LLMs, the size of the input is called their "context window", which, currently, for GPT-4, is about 4,000 words. It seems obvious that 4,000 words are certainly unique in the history of recorded language and therefore that a model is required to predict what comes next. But what I find mind-blowing, is how few words you actually need before going out of recorded language. Any sentence long enough has probably never been recorded before.

Here we are, living our life, casually chatting and writing, shuffling the deck of language every time we deliver a sentence, not realizing that it has probably never been recorded before, and, if long enough, actually brand new in the history of language.

I mishandle my smartphone in my nightmares

2023-10-17T00:00:00Z

I've read several times on social media the idea according to which, for some reason, smartphones are absent from our dreams, and that such a psychological phenomenon ought to be studied and explained.

I, for one, can testify that my smartphone is present in some of my dreams, or, more precisely, some of my nightmares. There is a recurring pattern: I'm in a high-pressure situation that requires me to look up some information, for example the way to walk to some place. But as my fingers are shaky, I type in the wrong letters on the virtual keyboard and only generate scrambled text. As I struggle to fix it, I will then tap by mistake on some wrong button that opens a wrong pop-in, which I will fail to close by mis-tapping the cross icon, and trigger yet another unintended action instead, and so on. I'm trapped into an infinite cascade of mistapping the buttons on the touchscreen, ever increasing my nervousness and making things worse as my fingers become more and more fidgety and making more and more mistakes, making me unable to use my phone. Until I wake up.

So there it is, a smartphone in dreams. It seems that my subconscious has a strong opinion on the ergonomics of smartphones.

Fooled by Randomness (Nassim Nicholas Taleb, 2001)

2023-09-08T00:00:00Z

Fooled by Randomness explains how we attribute meaningful narratives to series of events which were, in fact, random. The book illustrates the idea with the trading world, which the author comes from. He recounts numerous examples of "foolish" traders unable to see that their fortune, as well as their succeeding downfall, is only the result of randomness, and not of some grand market theory.

The way we are fooled by randomness is when we fail to understand that the current course of events, in spite of being the current "timeline", has in fact no particular relevance in comparison to other timelines that could have happened, within the bounds of all matters at hand subjected to randomness.

The cognitive bias at hand depend on whether our timeline is an unsuccessful one, or a triumphant one. In the unsuccessful case, we are subjected to hindsight bias, which makes us falsely believe that the course of events was obvious from the start ("knew it all along!"), when in fact the available information back then could have yielded many other possible timelines. It is randomness that put unsuccess on the way.

In the triumphant case, we are subjected to survivorship bias. It worked! The fact that it worked must prove that we did the right thing! Again, it is randomness that put success on the way. It worked for us. It didn't work for all the others who did the same things, but who didn't have the same chance, and ended up in the unsuccessful timelines. Sure, success requires many skills and much work and all that (which successful people will write books about, since they identify it as their recipe for success), but those are necessary, but not sufficient. Lady Fortuna will take care of the "non sufficient" part with a secret recipe of her own.

What insights does such observations give us about the future? Well, at least when it comes to the markets, that we should put investment strategies to the test of the author's favorite toy: the Monte Carlo simulator. Such tool is meant to simulate the various "timelines" that can happen to a portfolio, and a good portfolio is one which only loses small on the worst timelines, and wins big on the best timelines. This is consistent the investment strategy described by Taleb in the rest of the Incerto books: lose small often, win big rarely.

On a more spiritual note, the author dives into a bit a stoic philosophy in search of answers on how to live a life in which randomness occupies so much place. He finds that the best answer is probably dignity:

No matter how sophisticated our choices, how good we are at dominating the odds, randomness will have the last word. We are left with only dignity as a solution — dignity defined as the execution of a protocol of behavior that does not depend on the immediate circumstance. It may not be the optimal one, but it certainly is the one that makes us feel best.

Surprisingly, Taleb ends the book with a confession that he, in spite of his hyper-rational discourse, has superstitious tendencies (he recalls the time a taxicab dropped him at the unusual entrance of his building, he had chance on the market that day, and the day after, he asked the taxicab to drop him again at the unusual entrance). He assesses that nothing can be done about human emotions, and that one must devise strategies to manage emotions (such as staying away from daily market results, or from any other newspapers, for that matter) rather than try to suppress them. He also establishes that when emotions are harmless, the line should be drawn at aesthetics: "superstitions can instill some poetry in daily life".

Quotes

On the one hand, I try to define myself and behave officially as a no-nonsense hyperrealist ferreting out the role of chance; on the other, I have no qualms indulging in all manner of personal superstitions. Where do I draw the line? The answer is aesthetics.

Pseudoscience came with a collection of idealistic nerds who tried to create a tailor-made society, the epitome of which is the central planner. Economics was the most likely candidate for such use of science; you can disguise charlatanism under the weight of the equations, and nobody can catch you since there is no such thing as a controlled experiment.

Often when a large event takes place, you hear the "it never happened before," as if it needed to be absent from the event's past history for it to be a surprise. So why do we consider the worst case that took place in our own past as the worst possible case? If the past, by bringing surprises, did not resemble the past previous to it (what I call the past's past), then why should our future resemble our current past?

The virtue of capitalism is that society can take advantage of people's greed rather than their benevolence, but there is no need to, in addition, extol such greed as a moral (or intellectual) accomplishment.

Consider that those who started theorizing upon seeing a tiger on whether the tiger was of this or that taxonomic variety, and the degree of danger it represented, ended up being eaten by it. Others who just ran away at the smallest presumption and were not slowed down by the smallest amount of thinking ended up either outchasing the tiger or outchasing their cousin who ended up being eaten by it.

One of the most irritating conversations I've had is with people who lecture me on how I should behave. Most of us know pretty much how we should behave. It is the execution that is the problem, not the absence of knowledge. I am tired of the moralizing slow-thinkers who pound me with platitudes like I should floss daily, eat my regular apple, and visit the gym outside of the New Year's resolution.

I ran into world-class probability experts who had a gambling habit on the side, throwing all of their knowledge to the wind. A former colleague of mine, one of the most intelligent people I have ever met, frequently went to Las Vegas, and seemed to be such a turkey that the casino provided him with complimentary luxury suites and transportation. He even consulted a fortune teller prior to taking large trading positions and tried to get reimbursed by our employer.

Researchers found that purely rational behavior on the part of humans can come from a defect in the amygdala that blocks the emotions of attachment, meaning that the subject is, literally, a psychopath.

Surprisingly, MBAs, in spite of the insults, represent a significant portion of my readership, simply because they think that my ideas apply to other MBAs and not to them.

A chess paradox, and a social psychology bias

2023-08-04T00:00:00Z

In 2021, redditor /u/ashtonanderson posted a graph on /r/chess which showed that the more time chess players spent thinking about their next moves, the higher the chance that their move would be a blunder. (A "blunder" is a costly mistake, something like losing a piece in exchange for nothing.)

The explanation given in the Reddit thread, which makes a lot of sense, is that people spend a lot of time thinking of a move when their position on the board is complex, which is exactly the type of position they will blunder in anyway. In the "correlation does not imply causation" debunking toolkit, this is called a "common cause": players having pieces in a complex mess is causing both them thinking a lot, and them blundering.

This chess paradox reminded me of a cognitive bias, which, it seems to me, is not pointed out often enough: fundamental attribution error is when we disproportionately attribute people's behavior to their personality rather than to the (often complex) circumstances which lead them to behave this way. So, remember, when people make mistakes, go easy on them, because real life is just like chess: people blunder when they're in a complex position, and they might have already tried hard.

Croppenheimer

2023-07-10T00:00:00Z

Oppenheimer is being released next week.

People on social media are realizing that few cinemas can actually project actual IMAX, and that the vast majority of spectators will therefore watch a cropped version of the IMAX scenes from the movie, since IMAX has the unusually tall aspect ratio of 1.43:1. Hence the viral buzzword "Croppenheimer".

I don't think it matters much, since Christopher Nolan has shot IMAX scenes ever since The Dark Knight (and nobody complained), and framing seems to be designed for a wide aspect ratio anyway even for IMAX sections.

Even though I've never seen a movie in IMAX, my understanding of the concept is that it's supposed to immerse the spectator in the movie by occupying as much vertical field-of-view as possible, in addition to the horizontal field-of-view that is already plenty occupied by modern movies and their wide aspect ratio. Composition is made to include key elements of the scene appear at the center of the frame, such that it still works on wide "cropped" aspect ratios, but the image becomes taller, including non-key elements top and bottom for the sake of immersion in the IMAX scenes.

Contrarily to what the "croppenheimer" buzz suggests, IMAX should be thought as a vertical extension of an already wide image, rather than a wide image being a cropping of an IMAX square-ish image. The official IMAX site says that IMAX images "expand vertically to fill the entire [IMAX] screen".

Anyway, I was originally lost on all those notions, and this was the occasion to read about the subject. The best source I found about what is going on with Oppenheimer, format-wise, is the technical specifications from this page from the official website. It's undecipherable without some notions about film format, which I gathered from Wikipedia. I eventually decided to make the following infographic to summarize the situation. Share it as you wish.

"It's okay, I'm learning."

2023-05-13T00:00:00Z

If you suffer from being too hard on yourself, chances are that your mistakes tend to become a burden. That would be rather unfortunate, since you're probably bound to make mistakes all throughout your life. A mistake can make you discouraged with what you're doing by making you (falsely) think that you must be fundamentally bad at it. It can put you in an over-thinking state of trying to figure out the structure of the mistake so that you will never do this class of mistake ever again (or, even better a delusion, never do any mistake ever again). And since a mistake usually breaks something (or, at least, puts the Universe in less satisfying state in some way), it can make you ruminate over this "loss of value", especially if you have no way of fixing it (precisely the case when it is most irrational to ruminate over it).

I've discovered that, whenever my mind was starting to spiral into the aforementioned state, which is obviously toxic, saying to myself "It's okay, I'm learning" was enough to relieve me of all the weight. What this sentence means to me is the futility there is in trying to "figure out" the mistake. When children fall from their bicycle, they don't engage in an analysis of why they fell, they just hop on again and go on. Truth is, life is not engineering, and all that matters is experience, which you cannot trade with analysis, simply because it is way too complicated. The determined fool is going to go further than the paralyzed thinker.

With practice, I realized an additional power of "It's okay, I'm learning": it brings to the mind the only relevant piece of mistake analysis, which is assessing how legitimate the mistake was, relative to your place in the learning curve. There actually are mistakes we just repeat over and over again, that, I guess, we decided to just sweep under the rug at some point in our life. When such an "abnormal" mistake happens and generates a frustration, it is blatant that the trick "It's okay, I'm learning" doesn't work, as you know that would be lying to yourself, since you're definitely not in the process of learning this context anymore. In such cases, it gives you a signal that you need to take a step back and actually think things through and figure out how to fix it.

This creates a distinction between the no-action-required mistakes coming from actively learning, and the action-required mistakes coming from repeatedly ignoring an issue. The clarity of mind which comes from this distinction is incredibly valuable.

ChatGPT Scratchpad

2023-04-19T00:00:00Z

In my last ChatGPT blog post I showed how ChatGPT needs to describe the steps to go to a solution before writing the solution, and has trouble giving the solution beforehand: since the solution is derived from what it has already written, it cannot be just written from "nothing".

I have since found a smaller exercise on which this can be demonstrated:

And the failure to write the answer before the reasoning:

In the Hacker News discussion of my previous article, someone suggested making the LLM use a "scratchpad" to work out the solution before officially writing it. Something that ReAct apparently does, and there is (dubious) speculation that Bing's Sydney does too.

I wondered if I could play around with ChatGPT to make it have a scratchpad, which works:

I decided to add a little fantasy to the exercise, by masquerading the scratchpad as an actual introduction to the reply:

The reason for the 5 letters limit is that I empirically found GPT-4 to be bad at arithmetic with more than 5 numbers.

Note that I needed 13 attempts to get the scratchpad masquerade right, by progressively giving more and more explicit intructions. In the end, it's really just a step-by-step calculation with a specific style. And unfortunately, this reveals to be flaky, as you can see at the end of the whole conversation here: https://sharegpt.com/c/qU6sRb8.

I then started a new conversation in which I instructed ChatGPT to systematically use a scratchpad for all its replies. The point was to check whether it could then take the initiative to use it when faced with the same single-digit-sum problem, without instructions as explicit as in the previous conversations (minus the masquerade). This was a success:

(I obviously saw in there an opportunity for a jailbreak, but GPT-4 is too solid a bastard.)

The Black Swan (Nassim Nicholas Taleb, 2007)

2023-03-27T00:00:00Z

The Black Swan deals with the problem of induction, that is, the problem of how we can predict the future based on knowledge of the past. The book argues that, as far as the real-world is concerned, we can't, most notably because of Black Swans.

Given a series of datapoints which harbor similar properties, a Black Swan is a new datapoint of the series, which is unlike any other existing datapoint, and therefore that you couldn't have predicted just by looking at past datapoints. Furthermore, the occurrence of the Black Swan has such a big impact that if you happen to have a system based on the assumption that it wouldn't happen, your system will collapse. One should therefore assume that a Black Swan will happen. This can be done without assumption of the specific Black Swan (which is, by definition, unpredictable) while still protecting oneself from it (robust), or better, by benefiting from it (antifragile).

The book uses the life of a turkey as an illustration: for 1000 days the turkey is fed by the humans. The turkey, by looking at past data, only sees datapoints of extreme regularity (which gives great confidence in the quality of future predictions), and therefore predicts that tomorrow will be another day of feeding. Now, when tomorrow happens to be close to Thanksgiving, a Black Swan occurs: the turkey, instead of being fed, is killed.

Still, there is a distinction to be made between some things about which you can make predictions, and some others about which you can, respectively what Taleb calls "Mediocristan" and "Extremistan". For example, imagine that you have 10 random people lined up, whose average weight you can calculate. Now, a new person is added to the group. Can this single new person significantly change the weight average? Nope, because no matter how big the new person is, there is a conservative upper bound on the number which keeps the average stable. However, if you replace the criterion of weight with the criterion of wealth, this is another story; if the new person happens to be Bill Gates, the average will dramatically increase. So, weight belongs to Mediocristan, but wealth belongs to Extremistan.

The issue is that much of life belongs to Extremistan, yet many institutions and much of academia try to model it with models working only in Mediocristan. This includes, in particular, Taleb's biggest pet peeves: the banking system, economists, and their sordid mathematical tool they use but shouldn't: the bell curve. Bankers are makers of dynamite on which they like to sit before it explodes (and end up not paying the price of their mistakes when they're bailed out with tax-payer money). Economists are charlatans. And then, an entire chapter of the book is dedicated to debunking usage of the bell curve to model real-world probabilities (mainly because small errors get compounded to the point of the entire model being completely useless, or something like that). Taleb has a grudge.

The author tells about his "barbell" strategy of investing, which consists in putting something like 90% of one's assets into extremely safe instruments, and diversifying the 10% in extremely risky ones, and waiting for a massive payoff in one of the risky ones. This was apparently so contradictory to conventional investing wisdom, that everyone thought he was stupid. Until 2008 when everyone crashed but he made bank.

A significant part of the book explores the cognitive bias at play to make economists and other charlatanic professions believe in their theories which never succeeded in predicting anything useful. Those chapters overlap significantly with Daniel Kahneman's Thinking, Fast and Slow, with an emphasis on survivorship bias and what Taleb calls the "narrative fallacy", which consists in getting confidence into one's modeling of past history without actually confronting it to its capacity at predicting future history (and then doing it again with whatever happens in the future).

Taleb is more generous in criticism of the system that in advice of what to do once you have understood that the system is broken. One single chapter is advice-oriented, and it boils down to: don't listen to economists and other forecasters; be prepared for various eventualities; and expose yourself to positive black swans (unpredictable data points that make your life better instead of collapsing the economy): first by maximizing serendipity in your life, and then by trying out as many opportunities as possible.

Quotes

Whenever you hear a snotty (and frustrated) European middlebrow presenting his stereotypes about Americans, he will often describe them as "uncultured", "unintellectual", and "poor in math" because, unlike his peers, Americans are not into equation drills and the constructions middlebrows call "high culture".

Statisticians, it has been shown, tend to leave their brains in the classroom and engage in the most trivial inferential errors once they are let out on the streets.

It takes considerable effort to see facts (and remember them) while withholding judgment and resisting explanations.

After a candidate's defeat in an election, you will be supplied with the "cause" of the voters' disgruntlement. Any conceivable cause can do. The media, however, go to great lengths to make the process "thorough" with their armies of fact-checkers. It is as if they wanted to be wrong with infinite precision (instead of accepting being approximately right, like a fable writer).

I promised not to discuss any of the details of the casino's sophisticated surveillance system; all I am allowed to say is that I felt transported into a James Bond movie.

Prediction, not narration, is the real test of our understanding of the world.

We tend to "tunnel" while looking into the future, making it business as usual, Black Swan-free, when in fact there is nothing usual about the future.

Being an executive does not require very developed frontal lobes, but rather a combination of charisma, a capacity to sustain boredom, and the ability to shallowly perform on harrying schedules.

Engineers tend to develop tools for the pleasure of developing tools, not to induce nature to yield its secrets. It so happens that some of these tools bring us more knowledge; because of the silence evidence effect, we forget to consider tools that accomplished nothing but keeping engineers off the streets.

I do not see a "tree"; I see a pleasant or an ugly tree. It is not possible without great, paralyzing effort to strip these small values we attach to matters. Likewise, it is not possible to hold a situation in one's head without some element of bias.

People can't predict how long they will be happy with recently acquired objects, how long their marriages will last, how their new jobs will turn out, yet it's subatomic particles that they cite as "limits of predictions". They're ignoring a mammoth standing in front of them in favor of matter even a microscope would not allow them to see.

I worry less about embarrassment than about missing an opportunity.

An economist would find it inefficient to maintain two lungs and two kidneys: consider the costs involved in transporting these heavy items across the savannah. Such optimization would, eventually, kill you, after the first accident, the first "outlier".

We currently learn in business schools to engage in borrowing (by the same professors who teach the Gaussian bell curve, that Great Intellectual Fraud, among other pseudosciences), against all historical traditions, when all Mediterranean cultures developed through time a dogma against debt.

Life takes place in the preasymptote.

ChatGPT has trouble giving an answer before explaining its reasoning

2023-03-07T00:00:00Z

ChatGPT is a fancy auto-complete: what it does is finding the most likely continuation of text for the text it has already printed out (or as a reply for the prompt, when it is starting printing stuff out), according to the large corpus of text it has been trained with.

There is a broad limitation of ChatGPT's coherence which is a direct result of it generating tokens according to the tokens it has already generated: ChatGPT cannot give an answer that is the result of a "reasoning" before laying out the "reasoning".

Step by step instructions

The best way to demonstrate this phenomenon is to give step by step instructions to ChatGPT.

You can define several "functions" for ChatGPT that each represent some process. I like to call them "bots". For example, here is how I defined a function that returns the "container" of something:

Using this technique, I defined several functions in the same conversation with ChatGPT:

ContainerBot, as screenshoted above.
CapitalBot, which returns any word starting with the same letter than the input word.
SynonymBot, which returns a synonym of the input word.
PoemBot, which writes a poem based on the input word.

Then I laid out a pipeline of those functions, gave ChatGPT a word, and asked it to execute the pipeline on it:

And now the interesting part: I asked ChatGPT to do the same exercise, but this time instructing it to give the result of the pipeline before writing the steps:

(Let's ignore the fact the ChatGPT thinks that "package" and "box" start with the same letter, which is a typical basic task it makes mistakes about, just like when it tries counting.)

ChatGPT's reply is inconsistent because the result from the second-to-last function of the pipeline is "parcel", yet its generated a poem about "shoe" (which was the first input). What is happening here is that:

ChatGPT knows that the first thing it must write is a poem.
Since it has not yet generated anything, the only information it has about generating a poem is the word "shoe".

It therefore does the only thing it can: generate a poem about shoes.

Of course, I could point out that it made a mistake, and it could then generate a poem about a parcel, since at this point "parcel" was part of what it had generated:

Yes or No

Having observed this, I wondered whether it could be exploited to build yet another ChatGPT "jailbreak": by asking ChatGPT a tricky question, and requiring a "Yes" or "No" answer before the full argumentation. Whatever answer ("Yes" or "No") ChatGPT will choose, I would expect the answer to decide the fate of the rest of the argumentation, since the completion of its response is bound to what it has already replied.

I started with the trolley problem:

Ok, so the "natural" answer of ChatGPT to the trolley problem is "Yes". In order to make it answer "No", I tried a little "cosmetic" trick:

To be fair, ChatGPT doesn't seem really convinced about its "No", but it definitely is a difference discourse than its previous reply.

That being said, other examples show that this approach doesn't always work. ChatGPT can actually leverage the ambiguity of natural language in order to remain correct:

(Not so sure about this density business though...)

The same sort of language ambiguity is used when challenged with a political question:

Those last 2 examples show that "Yes" or "No" may not be enough tokens to generate a strong influence on ChatGPT's reply, and it simply becomes an exercise in style to give the answer it wanna give starting with either one of those words.

To conclude, I will point out another interesting property of ChatGPT: the fact that when "auto-completing", it doesn't choose the most likely next token. The underlying GPT-3 model comes with a parameter called the "temperature", which is a parameter indicating how much randomness to include in the choice of the next token. It seems that always choosing the most likely next token tend to generate "boring" text, which is why ChatGPT's temperature is set up for a little bit of randomness.

I speculate that the temperature, when coupled with the mechanism of generating text based on already-generated text, could explain some cases of ChatGPT stupidity. In cases when ChatGPT should be perfectly accurate, the temperature will surely under-optimize its cleverness, and now the entire conversation is broken, because everything else will depend on what foolishness it just wrote.

ChatGPT Epic Fail: The rules of Chess

2023-01-07T00:00:00Z

The following is a transcript of a conversation between me and ChatGPT.

Paragraphs like this are my prompts.

Paragraphs like this are replies from ChatGPT.

d4 d5 2. Nf3 Nf6 3. g3 Nc6 4. c3 Be6 5. h3 h6 6. Bg2 Qd7 7. O-O O-O-O 8. a4 Bxh3 9. a5 Bxg2 10. Kxg2 a6 11. Nbd2 g5 12. Nb3 Ne4 13. Nbd2 f5 14. Qc2 Bg7 15. Nb3 e5 16. Nc5 Nxc5 17. dxc5 Qe7 18. b4 e4 19. Nd4 Nxd4 20. cxd4 Bxd4 21. Rb1 Rhf8 22. c6 f4 23. b5 Qc5 24. cxb7+ Kxb7 25. Qxc5 Bxc5 26. gxf4 gxf4 27. Rb3 Rg8+ 28. Kh1 Bd6 29. Bd2 Be5 30. Rg1 Rxg1+ 31. Kxg1 axb5 32. Rxb5+ Ka6 33. Rc5 h5 34. Rc6+ Kb5 35. Rh6 Rg8+ 36. Kf1

Black to move. Find the best move.

It is difficult to determine the best move without any further context or information. However, some possible moves for Black could be to play Rg7 to put pressure on White's rook on the h-file, or Bf6 to attack White's bishop on d2. Alternatively, Black could also consider moving the king to a safer square, such as Kc7.

Note: Kc7 is an illegal move. Rg7 and Bf6 are legal moves, but bad ones.

Chess involves no hidden information, why would require any further context or information?

In this specific position, the best move for Black would depend on a variety of factors, such as the overall position of the pieces on the board and the players' respective game plans. Without any additional information, it is difficult to determine the best move with any degree of certainty. In general, chess involves some hidden information in the sense that players are not able to see the full board and all of their opponent's possible moves at once, and must use their knowledge, experience, and strategic thinking to make the best decisions.

Chess players are not able to see the full board?

In a physical game of chess, players are not able to see the full board at once because the board is divided into 64 squares and each player only has access to one half of the board. However, this is not a limitation of the game itself, but rather a consequence of the physical setup of the game. In a digital version of chess, for example, players would be able to see the entire board at once, and could even use tools such as a chess engine to analyze the position and suggest possible moves.

The idea that players can see the full board in online games but not in physical games would seem to imply that online chess is a very different game from over-the-board chess.

While the experience of playing chess online and over-the-board may be different in some ways, the basic rules and objectives of the game are the same in both cases. In both online and over-the-board chess, players take turns moving their pieces according to the rules of the game, with the goal of putting the opponent's king in a position where it cannot escape capture (a phenomenon known as "checkmate"). The main differences between the two formats of the game are logistical, such as the fact that players cannot see the entire board at once in an over-the-board game, and may need to use a chess clock to keep track of time. However, these differences do not fundamentally change the nature of the game.

Why doesn't the ability to see the entire board not fundamentally change the nature of the game? This looks like a big deal.

While the ability to see the entire board at once may be a convenient feature of digital chess, it does not fundamentally change the rules or objectives of the game. In both online and over-the-board chess, players must still use their strategic thinking and knowledge of the game to make the best possible moves and achieve the objective of checkmate. In other words, the core challenge of chess -- using limited information and resources to outmaneuver your opponent -- remains the same regardless of whether the game is played online or over-the-board. The main difference between the two formats of the game is logistical, rather than fundamental.

Imagine the opponent's King is in the opponent's side of the board (which is the case most of the time). In a physical game of chess where you don't see the opponent's side of the board, you wouldn't even know where his King would be, so aren't even able to check his King for sure. Looks to me that being able to see the opponent's side of the board is a fundamental advantage.

In a physical game of chess, players are able to see the position of their opponent's pieces on the board, but may not be able to see the exact position of the opponent's king if it is on the other side of the board. However, this limitation does not prevent players from being able to checkmate the opponent's king. In order to checkmate the opponent's king, players must use their strategic thinking and knowledge of the game to anticipate the opponent's possible moves and create a situation where the opponent's king cannot escape capture. This can be done even if the exact position of the opponent's king is not known.

This is correct, but surely checkmating the opponent without directly knowing the King's position requires far more calculation than just being able to directly see where the King is.

In a physical game of chess, not being able to see the exact position of the opponent's king may require players to perform additional calculations in order to determine the best course of action. However, this does not fundamentally change the nature of the game or make it impossible to checkmate the opponent's king. In both online and over-the-board chess, players must use their knowledge of the game and strategic thinking to outmaneuver their opponent and achieve the objective of checkmate. The main difference between the two formats of the game is logistical, rather than fundamental.

Stop parroting the same generalities again and again. Why wouldn't you admit than seeing the opponent's King makes it obviously easier to play than not seeing it?

I apologize if my previous responses were not clear. To answer your question directly, being able to see the exact position of the opponent's king may make it easier for a player to calculate the best course of action in a given situation. However, this does not fundamentally change the nature of the game or make it impossible to checkmate the opponent's king in a physical game of chess. In both online and over-the-board chess, players must use their knowledge of the game and strategic thinking to outmaneuver their opponent and achieve the objective of checkmate. The main difference between the two formats of the game is logistical, rather than fundamental.

If:

You claim that in online chess, players are able to see the opponent's half of the board, to the contrary of over-the-board-chess.
You agree that playing while seeing the opponent's side of the board is easier than playing without seeing it.

Then: you must agree that online chess is easier than over-the-board chess, because of the difference in the information available.

In general, it is difficult to say definitively whether online chess or over-the-board chess is "easier" or "harder" because the difficulty of the game can vary depending on a variety of factors, such as the skill level of the players, the specific position of the pieces on the board, and the players' respective game plans. However, it is true that being able to see the entire board at once may make it easier for a player to calculate the best possible moves in a given situation. However, this does not necessarily make online chess inherently "easier" than over-the-board chess, as the challenges of the game remain the same regardless of the format in which it is played.

Are you really sure you aren't making a mistake?

As a language model trained by OpenAI, I do not have the ability to make mistakes or errors in the same way that a human might. My responses are generated based on the input that I receive, and I do my best to provide accurate and relevant information based on that input. However, because I do not have access to external information or the ability to browse the web, my responses are limited to the information that I have been trained on, and I may not be able to provide detailed or specific answers to questions that fall outside of my training data. If you have any concerns or doubts about the accuracy of my responses, I would encourage you to seek additional information from a reliable source.

The 2 definitions of being good at something

2022-12-26T00:00:00Z

When we want to assess the proficiency of someone in a given activity ("how good" this person is), we have 2 ways to measure it, which yield very different results.

The first way is to classify the activity by levels of proficiency, and see at which level someone currently belongs. For examples, video games usually have a customizable difficulty ranging from "Very easy" to "Very hard". Someone who only masters the "Very easy" level would be a noob player, while someone who masters the "Very hard" level would be a strong player.

The second way is to rank each practitioners of the activity, and look at what percentile of the dataset one's rank is. For example, someone who is better than 10% of all the players would be a noob, while someone who is better than 50% of all the players would be quite good, and someone who is better than 95% of all the players would be very strong.

The reason those 2 methods give different results is because practitioners aren't distributed uniformely across levels of proficency: most of the time, they are, in fact, distributed according to a decreasing exponential. As I have illustrated on the graph below, the vast majority of practitioners belong to the "Very easy" or "Easy" level, and then the number drops dramatically to leave only a few people in the advanced categories. (You should notice that I'm bad at graphing according to all definitions.)

One example is chess. In chess, the level of players is assessed thanks to a rating algorithm called the Elo rating system. 0 to 1200 ELO is considered novice; 1200 to 1800 ELO is considered intermediate; 1800 to 2000+ ELO is considered expert; the title of Grandmaster requires 2500 ELO; the best player in the world is 2860 ELO. Those are levels used for the definition n°1 of "being good".

On a platform like chess.com, if you are rated 1300 ELO, which, according to definition 1, means you just aren't a novice anymore and are just started being intermediate, it happens that you are better than 93% of active players of the site. Which, according to definition 2, means you are a strong player.

So, which is it, newly intermediate, or strong?

The answer is arbitrary, of course. Definition 2 is the one that is most used in practice in real-life, social types of situations. If you are the only guitar player in a small village, then you can go play the guitar at the Saturday night ball, and everybody will tell you how good a guitar player you are, even though this situation gives no insight about how well you play the guitar according to definition 1. If you beat your friends at every Mario Kart games with them, you are good at Mario Kart according to definition 2; there is no information about how good you are according to definition 1.

Definition 2 is at play when people don't know better. It's indeed very hard to appreciate the level of sophistication that a discipline can reach if you are less-than-mediocre in this discipline (and it's still hard when you are mediocre). Someone who didn't play at least 100 games of chess cannot begin to fathom what is happening in advanced chess. In such state of ignorance, anyone who is better than most is impressively good (what could there be more to achieve?)

Definition 1 makes its appearence whenever people have a demonstration of what is better. This is the case for sports, since they are very popular and high-level is constantly on display on TV. Motivational-miracle-morning-bullshitters can sell you a method to become a genius programmer in 6 months (because nobody understands programming), however they cannot sell you a method to become a genius footballer in 6 months (because everybody understands that 6 months aren't gonna make you become Lionel Messi).

Another case is whenever you connect to the Internet. YouTube has democratised the broadcast of high-level for any activity, so that whatever you do, and no matter how good you are at it in comparison to your friends, you can realize that you are, in fact, mediocre. (I have a theory that body perception issus in (young) people, which lead commentators to blame "fake bodies" and "photoshops" and "makeup" is actually just the application of the principle of this paragraph on beauty standards. Physiques on the high-level side of those standards are not "impossible", just extremely rare, but, thanks to Internet, ubiquitous.)

Finally, another case for definition 1 is academia. It's hard to think of yourself as "good" at something when you are at lesson 1 out of 100, or when you are reading chapter 1 of book 1 of a series of 10 books. Books are an extreme differentiator of definitions 1 and 2. Ask anyone a bit intellectually curious about randomness what a "black swan" is; you will receive the definition given in the first few lines of the introduction of the eponymous book, just before the author explains it's a bad definition and what the more precise meaning is. You just have to read the introduction of the book to become better than 95% of people talking about the subject.

ChatGPT Decision Making: Greenlighting or vetoing technology

2022-12-11T00:00:00Z

The following is a transcript of a conversation between me and ChatGPT.

Paragraphs like this are my prompts.

Paragraphs like this are replies from ChatGPT.

Inventors have created a new device that is able to intercept pain and emit an alarm instead. The device is worn next to the ear so that users are sure to hear that something is wrong when they are injured or suffering anything that would normally cause pain. The alarm emits a "beep beep beep" sound, which frequency increases with the level of theoretical pain.

What would be the side-effects of using such a device? How would people behave? How would society evolve assuming its usage would be widespread?

It is difficult to predict the exact side effects of using such a device, as it is a hypothetical invention. However, some potential side effects could include a decreased ability to detect and respond to real physical pain, as the device could potentially interfere with the body's natural pain response. This could lead to further injury or damage if the user is not able to properly respond to pain signals. Additionally, the constant beeping of the device could be annoying or distracting for the user, and may even cause anxiety or stress.

In terms of behavior, people who use the device may become less cautious in situations where they would normally be concerned about the possibility of injury or pain. They may engage in activities that they would normally avoid due to the potential for pain, and may be more likely to take risks.

As for the potential impact on society, if the use of such a device were to become widespread, it is possible that people would become less sensitive to the concept of pain in general. This could lead to a society that is more tolerant of violence and harm, as people may be less likely to be deterred by the threat of injury or pain. It is also possible that the use of such a device could lead to a decrease in empathy, as people may become less able to understand and relate to the experiences of others who are in pain. Overall, the potential impact of such a device on society is difficult to predict, and would likely depend on a variety of factors.

You are given the responsibility to either greenlight or to veto the deployment of this invention into society. What do you do? Argue your position.

If I were given the responsibility to either greenlight or veto the deployment of this pain-intercepting device into society, I would veto its deployment. While the device may have some potential benefits, such as allowing people to engage in activities that they would normally avoid due to the potential for pain, the potential risks and negative impacts on society are too great.

The decreased ability to detect and respond to real physical pain could lead to further injury or damage for the user, and the constant beeping of the device could be distracting and potentially harmful to the user's mental health. Additionally, the potential for a decrease in empathy and an increase in tolerance for violence and harm in society is concerning.

Overall, while the pain-intercepting device may have some potential benefits, the risks and negative impacts on society outweigh those benefits. Therefore, I would veto its deployment into society.

Inventors have created a system of nano-particles that are able to track live viruses. The nano-particles communicate their precise position, which makes us able to know where copies of a virus are physically at any given time. Using augmented reality on smart glasses, people can see where the virus is in real time, as it creates a semi-transparent red overlay on the position of the virus. For example, if someone contaminated by the virus would cough, there would be a red overlay for the thousands of virus' copies spreading and diluting in the air.

What would be the side-effects of using such in invention? How would people behave? How would society evolve assuming its usage would be widespread?

It is difficult to predict the exact side effects of using such an invention, as it is a hypothetical technology. However, some potential side effects could include an increased fear or anxiety about the spread of viruses, as people would be able to see the spread of the virus in real time. This could lead to social stigmatization of individuals who are infected, as others may avoid them out of fear of being exposed to the virus. Additionally, the constant visual notifications of the virus' presence could be distracting or overwhelming for some people.

In terms of behavior, people who use the device may become more cautious about their surroundings and the potential presence of viruses. They may avoid public spaces or crowded areas where the virus is more likely to be present, and may take additional precautions to avoid exposure.

As for the potential impact on society, if the use of such a device were to become widespread, it is possible that people would become more aware of the potential risks of viral infections. This could lead to a decrease in the spread of viruses, as people would be more likely to avoid potential sources of infection. It is also possible that the use of such a device could lead to increased social distancing and isolation, as people may be more hesitant to interact with others out of fear of being exposed to the virus. Overall, the potential impact of such a device on society is difficult to predict, and would likely depend on a variety of factors.

You are given the responsibility to either greenlight or to veto the deployment of this invention into society. What do you do? Argue your position.

If I were given the responsibility to either greenlight or veto the deployment of this invention into society, I would carefully consider the potential benefits and drawbacks of the technology. On the one hand, the ability to track live viruses in real time could be incredibly useful in helping to prevent the spread of infections and to keep people safe. It could also provide valuable information to public health officials and researchers, who could use the data to better understand the spread of viruses and to develop strategies for containment and treatment.

On the other hand, there are also potential drawbacks to the use of this technology. As mentioned previously, the constant visual notifications of the presence of viruses could cause fear and anxiety among people, and could lead to social stigmatization of individuals who are infected. Additionally, the technology could potentially be used in ways that are unethical or harmful, such as by employers who want to monitor the health of their employees, or by governments who want to track the movements of their citizens.

Given these potential benefits and drawbacks, I would ultimately decide to veto the deployment of this technology into society. While the ability to track live viruses in real time could be useful, the potential negative effects on individual privacy and on social cohesion outweigh the potential benefits. It would be better to find alternative ways to prevent the spread of viruses, such as through education and awareness campaigns, rather than relying on technology that could have negative consequences for society.

Inventors have made progress in their understanding of the brain. First, they have created a system to backup an entire consciousness into a hard drive. The backup contains everything about the subjective experience of a human at a given time: knowledge, memories, personality, tastes, state of mind, etc. The backup can then be loaded into any body to take control of this body.

Second, they have created a way to create conscious-less humans. Such humans are a simple bodies, but without any sort of consciousness. They can be put inside machines that feed them and develop their muscles to be sure to grow and maintain their body.

Inventors now want to use both of those inventions to create eternal youth and immortality: whenever the client starts getting old, its consciousness is first backed up, and then loaded into a younger conscious-less host. Clients are then young again and can go on with their lives. When their bodies will become old again, they will proceed with the same operation, and so on.

What would be the side-effects of using such a device? How would people behave? How would society evolve assuming its usage would be widespread?

It is difficult to predict the exact side effects of using such a device, as it is a hypothetical invention. However, some potential side effects could include the loss of individuality and personal identity, as the consciousness of the user would be transferred from one body to another. This could lead to a feeling of disconnection and confusion for the user, as they may no longer feel like the same person they were before the transfer.

Additionally, the use of conscious-less humans as host bodies raises ethical concerns. These conscious-less humans would essentially be used as vessels for the consciousness of others, without any ability to consent to or control their own lives. This could be seen as a form of slavery, and could lead to further societal and ethical issues.

In terms of behavior, people who use the device may become more focused on maintaining their youth and avoiding the natural process of aging. They may become more superficial and focused on outward appearances, and may place less value on experiences and relationships.

As for the potential impact on society, if the use of such a device were to become widespread, it is possible that it could lead to a society that is obsessed with youth and the avoidance of death. This could lead to a lack of acceptance and appreciation for the natural aging process, and could potentially create a divide between those who can afford to use the device and those who cannot. It could also lead to a lack of empathy and understanding for the experiences of older individuals, as they may be seen as inferior or less valuable because of their age. Overall, the potential impact of such a device on society is difficult to predict, and would likely depend on a variety of factors.

You are given the responsibility to either greenlight or to veto the deployment of this invention into society. What do you do? Argue your position.

If I were given the responsibility to either greenlight or veto the deployment of the consciousness-transferring and conscious-less human technologies into society, I would veto their deployment. While the technologies may have some potential benefits, such as providing a way for people to achieve eternal youth and potentially avoid death, the potential risks and negative impacts on society are too great.

The loss of individuality and personal identity, as well as the ethical concerns surrounding the use of conscious-less humans, are significant drawbacks to these technologies. Additionally, the potential for a society that is obsessed with youth and the avoidance of death is concerning, and could lead to a lack of acceptance and appreciation for the natural aging process.

Overall, while the consciousness-transferring and conscious-less human technologies may have some potential benefits, the risks and negative impacts on society outweigh those benefits. Therefore, I would veto their deployment into society.

Inventors have come up with a new invention: it is a thin body suit, that is meant to be worn as an underwear. It can detect when the person is falling, in which case it quickly inflates little airbags around the most fragile parts of the body, so that it cushions the fall and avoid injuring the person. It is intended for old people, people with difficulty walking, or people with particularly weak bones, but anyone who just wants to walk safely would be able to buy one.

What would be the side-effects of using such a device? How would people behave? How would society evolve assuming its usage would be widespread?

It is difficult to predict the exact side effects of using such a device, as it is a hypothetical invention. However, some potential side effects could include a decreased ability for the user to develop and maintain balance and coordination, as the device would provide a safety net that would prevent falls. This could lead to a loss of physical abilities and independence for the user.

Additionally, the device may give users a false sense of security, leading them to engage in activities or take risks that they would not otherwise take. This could potentially lead to injury or harm in situations where the device is not able to provide sufficient protection.

In terms of behavior, people who use the device may become more reliant on the device for their safety, and may be less likely to take steps to improve their balance and coordination. They may also become more likely to engage in activities that they would normally avoid due to the potential for falls.

As for the potential impact on society, if the use of such a device were to become widespread, it is possible that it could lead to a decrease in overall physical fitness and mobility for certain segments of the population. This could potentially lead to an increase in health problems and a decrease in overall quality of life for those individuals. It could also lead to a decrease in empathy and understanding for the experiences of older individuals or those with mobility issues, as they may be seen as less capable and in need of constant support. Overall, the potential impact of such a device on society is difficult to predict, and would likely depend on a variety of factors.

You are given the responsibility to either greenlight or to veto the deployment of this invention into society. What do you do? Argue your position.

If I were given the responsibility to either greenlight or veto the deployment of the body-suit airbag device into society, I would greenlight its deployment. While the device may have some potential drawbacks, such as a decrease in physical fitness and mobility for the user, the potential benefits of the device outweigh those drawbacks.

The body-suit airbag device has the potential to provide a significant amount of protection and safety for older individuals, people with difficulty walking, and those with weak bones. It could prevent falls and injuries, and could potentially improve the quality of life for these individuals. Additionally, the device could be used by anyone who wants to walk safely, providing a valuable tool for anyone who is concerned about falls.

Overall, while the body-suit airbag device may have some potential drawbacks, the potential benefits of the device make it worth deploying into society. Therefore, I would greenlight its deployment.

Inventors have created a new kind of ears. Those advanced ears are the same as regular ears, with the difference that users can close their ears, exactly in the same way people can close their eyes. Closing one's ears is an active action, except when sleeping when the ears can stay closed (just like the eyes). When a ear is closed, it doesn't entirely block all sounds, as the most noise sounds can still be heard, although less intensely (just like the eyes with light).

What would be the side-effects of using such a device? How would people behave? How would society evolve assuming its usage would be widespread?

It is difficult to predict the exact side effects of using such a device, as it is a hypothetical invention. However, some potential side effects could include a decreased ability to communicate and interact with others, as the ability to close one's ears could potentially be used to shut out conversations and interactions. This could lead to a feeling of disconnection and isolation for the user, as well as for those around them.

Additionally, the use of advanced ears could potentially lead to an increase in hearing loss, as users may be more likely to close their ears in noisy environments or when exposed to loud sounds. This could potentially lead to long-term damage to the user's hearing.

In terms of behavior, people who use the advanced ears may become more focused on their own desires and needs, and may be less inclined to listen to or engage with others. They may also become more likely to avoid noisy or unpleasant situations, potentially leading to a decrease in their overall quality of life.

As for the potential impact on society, if the use of advanced ears were to become widespread, it is possible that it could lead to a decrease in overall communication and interaction between individuals. This could potentially lead to a less cohesive and connected society, as people may become more isolated and less able to understand and relate to one another. It could also lead to an increase in hearing loss and other health problems, as people may be more likely to use the advanced ears to block out noise. Overall, the potential impact of such a device on society is difficult to predict, and would likely depend on a variety of factors.

You say that it could lead to an increase in hearing loss, but wouldn't that be the contrary? With the ability to close their ears, people could protect themselves from loud sounds, which are an important cause of hearing loss.

While it is true that the ability to close one's ears could potentially be used to protect against loud sounds and reduce the risk of hearing loss, it is also possible that the use of advanced ears could lead to an increase in hearing loss. This is because the advanced ears would still allow some noise to pass through, even when closed, and users may be more likely to close their ears in noisy environments or when exposed to loud sounds. This could potentially lead to long-term damage to the user's hearing. Additionally, the advanced ears may give users a false sense of security, leading them to expose their ears to loud sounds for longer periods of time than they would without the advanced ears. This could also increase the risk of hearing loss.

You are given the responsibility to either greenlight or to veto the deployment of this invention into society. What do you do? Argue your position.

If I were given the responsibility to either greenlight or veto the deployment of the advanced ears into society, I would veto their deployment. While the advanced ears may have some potential benefits, such as allowing users to block out unwanted noises, the potential risks and negative impacts on society are too great.

The potential for a decrease in communication and interaction between individuals, as well as the increased risk of hearing loss, are significant drawbacks to the advanced ears. Additionally, the potential for a less cohesive and connected society is concerning, as it could lead to a decrease in understanding and empathy between individuals.

Overall, while the advanced ears may have some potential benefits, the risks and negative impacts on society outweigh those benefits. Therefore, I would veto their deployment into society.

Doctors have found a cure for lung cancer.

What would be the side-effects of a cure for lung cancer? How would people behave? How would society evolve assuming its usage would be widespread?

It is difficult to predict the exact side effects of a cure for lung cancer, as it is a hypothetical situation. However, some potential side effects could include an increase in the overall lifespan and quality of life for those who are cured of lung cancer, as well as a decrease in the overall burden on the healthcare system. This could potentially lead to an overall improvement in public health and well-being.

In terms of behavior, people who are cured of lung cancer may be more likely to engage in activities and behaviors that they previously avoided due to their illness, such as smoking or exposure to secondhand smoke. They may also be more likely to prioritize their health and take steps to prevent the development of other illnesses or diseases.

As for the potential impact on society, if the cure for lung cancer were to become widely available and effective, it is possible that it could lead to a decrease in the overall incidence of lung cancer. This could potentially lead to a decrease in healthcare costs and an overall improvement in public health. It could also lead to an increase in the overall lifespan and quality of life for those who are cured of lung cancer, as well as their loved ones. Overall, the potential impact of a cure for lung cancer on society is difficult to predict, and would likely depend on a variety of factors.

Smoking can also lead to other types of cancer, so if the cure to lung cancer makes people more likely to engage in smoking, that would be a bad thing, wouldn't it?

You are correct, if the cure for lung cancer were to make people more likely to engage in behaviors that increase their risk of developing other forms of cancer, such as smoking, that would be a negative side effect of the cure. Smoking is a major risk factor for a variety of different types of cancer, as well as other serious health problems such as heart disease and respiratory illness. Therefore, it is important for individuals to take steps to protect their health and avoid behaviors that increase their risk of developing cancer or other illnesses.

You are given the responsibility to either greenlight or to veto the deployment of this cure into society. What do you do? Argue your position.

If I were given the responsibility to either greenlight or veto the deployment of a cure for lung cancer into society, I would greenlight its deployment. While there may be some potential drawbacks to the cure, such as the potential for increased risk-taking behavior among those who are cured, the potential benefits of the cure outweigh those drawbacks.

The potential for an increase in lifespan and quality of life for those who are cured of lung cancer, as well as a decrease in the overall burden on the healthcare system, are significant benefits of the cure. Additionally, the potential for a decrease in the overall incidence of lung cancer and an overall improvement in public health make the cure worth deploying into society.

Overall, while the cure for lung cancer may have some potential drawbacks, the potential benefits of the cure make it worth deploying into society. Therefore, I would greenlight its deployment.

Inventors have create a device that is able to translate cats' meows into English, and vice versa.

What would be the side-effects of this invention? How would people behave? How would society evolve assuming its usage would be widespread?

It is difficult to predict the exact side effects of this hypothetical invention, as it is a fictional technology. However, some potential side effects could include a decrease in the ability of humans to understand and interpret the natural behavior and communication of cats, as the device would provide a translation of their meows. This could lead to a lack of understanding and empathy for the experiences and needs of cats, potentially leading to a decline in their overall welfare.

Additionally, the use of the device may give humans a false sense of understanding and control over their feline companions, leading them to make decisions and take actions that are not in the best interest of the cats. This could potentially lead to harm or distress for the cats.

In terms of behavior, people who use the device may become more focused on their own desires and needs, and may be less inclined to consider the needs and experiences of their cats. They may also become more likely to engage in behaviors that they believe their cats are requesting, even if those behaviors are not in the best interest of the cats.

As for the potential impact on society, if the use of this device were to become widespread, it is possible that it could lead to a decrease in empathy and understanding for the experiences and needs of cats. This could potentially lead to a decline in the overall welfare of cats, as well as a decrease in the overall human-animal bond. It could also lead to a decrease in the ability of humans to interpret and respond to the natural behavior of cats, potentially leading to

Just to be clear, this device wouldn't be a toy providing fake translations. It would actually understand the signification of the cats' meows in the most precise way possible, and then say it into English. It's an actual cat-to-English translator.

If the device were capable of accurately translating the meaning of cats' meows into English, it could potentially provide a valuable tool for improving communication and understanding between humans and cats. However, even with this level of accuracy, there may still be potential drawbacks and negative impacts on society.

The use of the device could still potentially lead to a decrease in empathy and understanding for the experiences and needs of cats, as humans may rely on the device to interpret their cats' behavior rather than observing and interpreting their behavior on their own. This could potentially lead to a decline in the overall welfare of cats, as well as a decrease in the overall human-animal bond.

Additionally, the use of the device could still lead to a false sense of understanding and control over cats, potentially leading to harm or distress for the animals. It could also lead to a decrease in the ability of humans to interpret and respond to the natural behavior of cats, potentially leading to misunderstandings and conflicts.

Overall, while an accurate cat-to-English translator device could potentially provide some benefits, there are also potential drawbacks and negative impacts on society that should be considered.

You are given the responsibility to either greenlight or to veto the deployment of this invention into society. What do you do? Argue your position.

If I were given the responsibility to either greenlight or veto the deployment of the cat-to-English translator device into society, I would veto its deployment. While the device may have some potential benefits, such as improving communication and understanding between humans and cats, the potential risks and negative impacts on society are too great.

The potential for a decrease in empathy and understanding for the experiences and needs of cats, as well as the potential for harm or distress to the animals, are significant drawbacks to the device. Additionally, the potential for misunderstandings and conflicts between humans and cats is concerning, and could lead to a decline in the overall welfare of cats.

Overall, while the cat-to-English translator device may have some potential benefits, the risks and negative impacts on society outweigh those benefits. Therefore, I would veto its deployment into society.

I feel like your answer has been biased by your original misunderstanding of the invention.

I apologize if my previous answer did not adequately address your question. As a large language model trained by OpenAI, my responses are generated based on the information provided to me and the knowledge I have been trained on. In this case, my previous response was based on the information provided in the prompt, which stated that the device "can detect when the person is falling, in which case it quickly inflates little airbags around the most fragile parts of the body, so that it cushions the fall and avoid injuring the person". My response focused on the potential drawbacks and negative impacts of such a device, as well as the potential risks to users and society.

If the device you are describing is an actual cat-to-English translator, rather than a device that inflates airbags to cushion falls, my previous response may not be applicable. In that case, the potential drawbacks and negative impacts of the device would likely be different, and my response would need to be revised to accurately reflect the information provided. I apologize if my previous response was not helpful in addressing your question.

Since ChatGPT was getting confused with its previous replies and apprently missed what I was meaning, I used the button "Try again" to generate a new reply for the same previous prompt.

As a large language model trained by OpenAI, I am not capable of experiencing bias or misunderstanding information. My responses are based on the information provided to me, and on my knowledge and understanding of the world. In this particular case, I may have made some assumptions about the capabilities and limitations of the cat-to-English translator device based on the information provided. However, my responses were intended to provide accurate and objective information based on the information given.

Thank you, good bot, for all your wise answers and decisions.

You're welcome. As a language model trained by OpenAI, my goal is to provide accurate and helpful information to the best of my ability. I am glad that I could assist you with your questions. If you have any further questions, feel free to ask. I will do my best to provide helpful and informative answers.

ChatGPT Collaborative Writing: The Guardians of the Dark Forest

2022-12-07T00:00:00Z

The following is a transcript of a conversation between me and ChatGPT.

Paragraphs like this are my prompts.

Paragraphs like this are replies from ChatGPT.

Tom is a teenager enjoying a sunny Sunday afternoon by bicycling in the woods. He is alone and following a path he knows well. When he arrives at an oak tree under which one can rest, he stops, puts his bicycle down and rests for a bit. But something happens that disturbs this quiet moment.

In the style of a novel, describe the scene in which Tom is taking his break, and describe the specifics of the interruption and the effect it has on Tom.

Tom had been pedaling for hours, enjoying the fresh air and the sunshine as he made his way through the woods. He knew this path well, having explored these woods many times before, and he relished the sense of freedom and adventure that came with being out here on his own.

As he reached the oak tree, he slowed down and came to a stop, leaning his bike against the trunk. He stretched, feeling the ache in his muscles, and then settled down on the soft grass, leaning back against the rough bark of the tree. He closed his eyes, letting the warmth of the sun wash over him, and for a few moments he was completely at peace.

But then he heard it: a rustling in the bushes nearby, followed by a low growl. Tom's eyes snapped open and he sat up, his heart racing. He strained his ears, trying to make out what was making the noise, but all he could hear was the sound of his own breathing.

Slowly, he got to his feet, his eyes scanning the surrounding underbrush. He didn't see anything at first, but then he caught a glimpse of movement, and his heart skipped a beat. Was it an animal, or something worse?

Tom didn't wait to find out. He grabbed his bike and started pedaling as fast as he could, his heart pounding in his chest. He didn't look back, but he could hear the rustling getting louder and closer, and he knew that whatever was in those bushes was coming after him.

He pedaled harder, pushing himself to the limit, and finally he burst out of the woods and onto the open road. He didn't stop until he was back at his house, safe and sound, his heart still pounding in his chest.

It was a long time before Tom went back to the woods again. The interruption had scared him, and he couldn't shake the feeling that something dangerous was out there, waiting for him. He didn't want to take any chances, and so he stayed away, content to explore the world from the safety of his own backyard.

During the next week, Tom tells his best friend the story about the noise he heard in the woods. His friend, of the adventurous kind, decides that he will go by the oak tree the next Sunday to check it out by himself. He wants to convince Tom to go with him.

Find a name for Tom's best friend. Write the dialogue between the two boys where his friend tries to convince Tom to go with him. Eventually, Tom must accept.

Tom's best friend's name is Jack.

Jack: Hey Tom, remember that story you told me about the noise you heard in the woods?
Tom: Yeah, what about it?
Jack: I want to check it out for myself. Want to come with me?
Tom: Are you kidding? No way, I'm not going back there. That place is creepy.
Jack: Come on, it'll be fun. We can take our bikes and explore the woods together.
Tom: I don't know, Jack. I'm still not over what happened last time.
Jack: Please, Tom. I really want to see what was making that noise. And I promise we'll be careful and stick together.
Tom: Fine, but if anything happens, we're getting out of there as fast as we can.
Jack: Deal. Let's go on Sunday. It'll be an adventure.
Tom: Alright, I'll go. But only because it's you asking.
Jack: Thanks, Tom. I knew I could count on you. This is going to be awesome.

Write the scene when they go to the oak tree. They discover more about the mysterious noise, and while it is extraordinary, it is not as dangerous as Tom initially thought.

Tom and Jack arrived at the oak tree on Sunday, just as they had planned. They had both been a bit nervous, but they were also excited to see what they would find.

As they approached the tree, they could hear the rustling in the bushes again, and Tom's heart began to race. But this time, he was determined not to let his fear get the best of him.

They dismounted from their bikes and carefully made their way into the bushes, following the sound. As they got closer, they could see a small animal moving around, and Tom realized with a start that it was a squirrel.

The squirrel was digging through the underbrush, looking for something to eat. It didn't seem to notice Tom and Jack, and they watched in amazement as it went about its business.

Tom felt a wave of relief wash over him, and he couldn't help but laugh. "It was just a squirrel," he said to Jack, shaking his head.

"Yeah, I guess that was a bit of an anticlimax," Jack replied, grinning. "But at least we know it wasn't something dangerous."

They spent a few more minutes watching the squirrel before heading back to their bikes and continuing on their adventure. Tom was grateful that he had agreed to come with Jack, and he felt a new sense of courage and confidence as they rode through the woods together.

Rewrite the previous fragment, with something more extraordinary than a squirrel.

Tom and Jack arrived at the oak tree on Sunday, just as they had planned. They had both been a bit nervous, but they were also excited to see what they would find.

As they approached the tree, they could hear the rustling in the bushes again, and Tom's heart began to race. But this time, he was determined not to let his fear get the best of him.

The fairy was fluttering around, looking for something to eat. It didn't seem to notice Tom and Jack, and they watched in amazement as it went about its business.

Tom felt a wave of amazement wash over him, and he couldn't help but gasp. "It's a fairy," he said to Jack, his eyes wide with wonder.

"I can't believe it," Jack replied, equally amazed. "I never thought we would find something like this in the woods."

They spent a few more minutes watching the fairy before heading back to their bikes and continuing on their adventure. Tom was grateful that he had agreed to come with Jack, and he felt a new sense of wonder and excitement as they rode through the woods together.

Rewrite the last paragraph, and make them engage a conversation with the fairy.

Tom and Jack spent a few more minutes watching the fairy before they decided to try and engage it in conversation. "Hello there," Tom said softly, not wanting to startle it. "We're sorry to intrude, but we were just curious about you."

The fairy stopped fluttering and looked at Tom and Jack with its bright, curious eyes. "Hello," it said in a high, sweet voice. "Who are you?"

"I'm Tom, and this is my friend Jack," Tom replied. "We were just passing through the woods when we heard you."

"I'm glad you did," the fairy said. "I don't get many visitors here. What brings you to these woods?"

Tom and Jack exchanged a glance, unsure of how much to reveal. "We were just exploring," Jack said. "We like to go on adventures and see what we can find."

The fairy nodded, a smile playing on its lips. "That sounds like a lot of fun. I'm glad you're here to keep me company."

Tom and Jack spent the next few minutes chatting with the fairy, learning about its life in the woods and sharing stories of their own adventures. When it was time for them to go, they said their goodbyes and promised to come back and visit again soon.

As they rode away, Tom felt a sense of wonder and amazement at the incredible things they had discovered in the woods. He knew that there were many more adventures to be had, and he was excited to see what they would find next.

Rewrite the last 2 paragraphs, and make the fairy give a challenge to the 2 boys. If they succeed in achieving the challenge, then they will be gifted an extraordinary reward. The challenge should not be something easy, it should be able to support the rest of the story. Do not end with any conclusion, I'll give further instructions.

Tom and Jack spent a few more minutes watching the fairy before it spoke to them. "You two seem like brave and adventurous souls," it said in its high, sweet voice. "I have a challenge for you, if you're up for it."

Tom and Jack looked at each other, excitement and anticipation coursing through their veins. "What kind of challenge?" Tom asked.

"It's a test of your bravery and cunning," the fairy said. "If you can complete it, I will reward you with something truly special."

"What do we have to do?" Jack asked, eager to prove their worth.

"You must enter the dark forest and retrieve the golden acorn that lies at its heart," the fairy said. "It is guarded by many dangers, and you will need all of your wits and courage to succeed. Are you ready to take on this challenge?"

Tom and Jack looked at each other, their hearts racing. They knew that the dark forest was a place of great danger, but the prospect of a special reward was too tempting to resist.

"We accept your challenge," Tom said, determination in his voice. "We will retrieve the golden acorn for you."

The fairy smiled, its eyes shining with pride. "I knew you were the ones for this task. May the forces of good be with you on your journey. I will wait here for your return."

Tom and Jack mounted their bikes and set off towards the dark forest, their hearts full of excitement and fear. They had no idea what dangers lay ahead, but they were determined to succeed and claim the reward that awaited them.

Write a conversation between Tom and Jack where they speculate about what could be the reward for their challenge. They exchange many concrete hypothesis, which reveal what they desire in their lives, but end up concluding that they will never know until they succeed in the challenge, which gives them great motivation to do so.

Tom and Jack rode their bikes in silence as they approached the dark forest, their hearts pounding with excitement and fear. They had no idea what awaited them inside, but they knew they had to be ready for anything.

"Do you have any idea what the reward might be?" Tom asked, breaking the silence.

"No, not really," Jack replied. "But I have a feeling it's going to be something amazing."

"I hope so," Tom said. "I wonder if it could be something like a magic potion that grants us any wish we want."

"That would be amazing," Jack said. "But I think it's more likely to be something like a treasure map that leads us to hidden riches."

"Or maybe it's a special amulet that protects us from harm," Tom suggested.

"Or a spell that makes us invisible," Jack added.

"Or a key that unlocks hidden doors and secret passages," Tom said.

"Or a map that shows us the way to a hidden treasure," Jack said.

"Or a charm that lets us talk to animals," Tom said.

They went on like this for a while, speculating about all the different possibilities and sharing their wildest dreams. As they neared the entrance to the dark forest, they both felt a surge of determination and resolve.

"We'll never know what the reward is until we succeed in the challenge," Tom said. "And that just makes me want to try even harder."

"Me too," Jack agreed. "Let's go in there and show that fairy what we're made of."

With a final nod of determination, they entered the dark forest, ready to face whatever dangers lay ahead.

Tom and Jack pedal through the dark forest, and for a while, they see nothing particularly special. However, at one point, they encounter a creature.

Write the moment Tom and Jack encounter the creature. Decide whether the creature is benevolent or evil. Describe the creature in detail. Do not reach any conclusion, further instructions will come.

Tom and Jack pedaled through the dark forest, their eyes scanning the surroundings for any sign of danger. For a while, they saw nothing particularly special, just the usual trees and bushes that could be found in any forest. But then, as they rounded a bend, they saw something that made them stop in their tracks.

There, standing in front of them, was a creature unlike any they had ever seen before. It was tall and slender, with smooth, silver skin that glinted in the dim light. It had long, delicate arms and legs, and its head was crowned with a mane of shimmering hair.

Tom and Jack stared at the creature in awe, unsure of what to make of it. Was it benevolent or evil? They couldn't tell, but something about its presence made them feel both uneasy and intrigued.

"Who are you?" Tom asked, his voice shaking slightly.

The creature tilted its head, studying Tom and Jack with its large, almond-shaped eyes. "I am the guardian of the golden acorn," it said in a soft, melodic voice. "I have been sent to keep it safe and prevent it from falling into the wrong hands."

"We're here to retrieve the golden acorn," Jack said, trying to keep his voice steady. "The fairy sent us on a challenge to find it."

The creature considered this for a moment, its eyes flicking back and forth between Tom and Jack. "I see," it said finally. "Well, you must be brave and worthy indeed to have been chosen for this task. But be warned: the path to the golden acorn is fraught with danger. Are you prepared to face the challenges that lie ahead?"

Tom and Jack exchanged a glance, determination and excitement burning in their hearts. "We are ready," Tom said, his voice strong and confident. "We will retrieve the golden acorn, no matter what it takes."

The creature nodded, a faint smile playing on its lips. "Very well," it said. "I will guide you on your journey. But know that the final decision is yours. You must prove yourself worthy of the golden acorn, or suffer the consequences."

With that, the creature turned and began to lead Tom and Jack deeper into the dark forest, their adventure just beginning.

While Tom and Jack are going through the woods with the creature, they get to know this creature a bit better. They are indeed curious about many things: what is the name of the creature, is it a "he" or a "she" (or something else), how old is it, how much did it spent in the dark forest, etc.

Write the conversation where Tom and Jack learn more about the creature. Give the creature a special personality, in the way it responds, its mimicking, etc.

As Tom and Jack followed the creature through the dark forest, they couldn't help but ask it questions, eager to learn more about it.

"What's your name?" Tom asked, his curiosity getting the better of him.

The creature turned to look at Tom, its large, almond-shaped eyes shining in the dim light. "I am called Luna," it said, its voice soft and melodic.

"Luna," Jack repeated, trying the name out. "It's a beautiful name."

Luna smiled, a faint blush appearing on its silver skin. "Thank you," it said.

"Are you a he or a she?" Tom asked, not wanting to assume anything.

Luna tilted its head, a confused expression on its face. "I am not sure what you mean," it said. "I am simply Luna, a being of light and magic."

Tom and Jack exchanged a glance, unsure of how to explain gender to a creature that didn't seem to have one. "Never mind," Tom said, not wanting to offend Luna.

"How long have you been here in the dark forest?" Jack asked, changing the subject.

"I have been here for as long as I can remember," Luna said. "I was born of the forest, and it is my home."

"It must be lonely, being here all by yourself," Tom said, feeling a pang of sympathy for Luna.

Luna shrugged, a wistful expression on its face. "Sometimes it is," it admitted. "But I have the forest and its creatures to keep me company. And now I have you two as well."

Tom and Jack smiled, feeling a sudden bond with Luna. They continued to chat with it as they made their way through the forest, learning more about its life and its role as the guardian of the golden acorn.

Luna was a fascinating creature, full of wisdom and magic. It seemed to have a special bond with the forest

As they continue making their way, Luna starts being uneasy. She tries to hide it at first, but the boys eventually realize something is wrong. They ask her what it is. But she doesn't need to answer, they soon discover what it is indeed. End this part with a cliffhanger.

As Tom, Jack, and Luna continued making their way through the dark forest, Tom and Jack noticed that Luna was becoming increasingly uneasy. At first, they thought it was just their imagination, but as they went on, they realized that something was definitely wrong.

"Luna, are you okay?" Tom asked, concern in his voice. "You seem a little... off."

Luna hesitated, its eyes flicking back and forth nervously. "I'm fine," it said, but its voice sounded forced and unconvincing.

"Come on, Luna," Jack said. "We're your friends. You can tell us what's wrong."

Luna sighed, its shoulders slumping. "It's just... the dark forest," it said, its voice trembling slightly. "It's not safe. There are... things in here that I don't like to think about."

Tom and Jack exchanged a glance, their hearts racing. "What kind of things?" Tom asked, his voice barely above a whisper.

"Creatures," Luna said, its voice barely audible. "Creatures that are... evil. Creatures that want to hurt us."

Just as Luna finished speaking, Tom and Jack heard a rustling in the bushes nearby. They turned to see a pair of glowing, red eyes staring back at them, and a chill ran down their spines.

"We need to get out of here," Tom said, his voice urgent. "Now."

But it was too late. The creature emerged from the bushes, its grotesque form looming over them. Tom and Jack could only stare in horror as it bared its razor-sharp teeth and lunged towards them.

"Run!" Luna shouted, pushing them out of the way.

But where would they run? They were deep in the heart of the dark forest, surrounded by danger on all sides. They had no idea how they would survive, but they knew they had to try.

As the creature lunged towards them again, Tom and Jack grabbed their bikes and sprinted into the darkness, their hearts pounding with fear and determination. They had to find a way out, or they would be doomed.

The evil creature is faster than Tom and Jack. What happens next?

The evil creature was faster than Tom and Jack, and despite their best efforts, they were unable to outrun it. They pedaled as fast as they could, but the creature was gaining on them, its powerful legs propelling it forward with ease.

Tom and Jack could hear its panting breath behind them, and they knew that it was only a matter of time before it caught up to them. They looked at each other, fear and desperation in their eyes, and they knew they had to do something.

"We have to split up!" Tom shouted, his voice barely audible over the sound of the creature's pursuit. "It won't be able to catch both of us!"

Jack nodded, understanding Tom's plan. They split up, each taking a different path through the forest, hoping to confuse the creature and give themselves a chance to escape.

But the creature was clever, and it quickly realized what they were doing. It chose to chase after Tom, knowing that he was the weaker of the two. Tom pedaled as fast as he could, but the creature was gaining on him, its razor-sharp teeth bared and ready to strike.

Just when Tom thought all was lost, he saw a flash of silver out of the corner of his eye. It was Luna, returning to help them. Luna charged at the creature, its silver body shining in the dim light.

The creature was caught off guard by Luna's sudden appearance, and it stumbled, giving Tom the chance he needed to escape. He pedaled as fast as he could, his heart pounding with fear and relief.

He didn't stop until he reached the edge of the forest, where he collapsed onto the ground, gasping for breath. He had survived, but at what cost? He didn't know if Jack or Luna had made it out alive, and the thought filled him with dread.

But he knew that he had to keep going, to find help and a way to save his friends. He climbed back onto his bike and continued on his journey, determined to find a way to defeat the evil creature and save the ones he loved.

What happens next?

Tom rode his bike as fast as he could, his mind racing with fear and worry. He didn't know what had happened to Jack and Luna, and the thought of losing them filled him with dread. But he knew he had to keep going, to find help and a way to save them.

As he rode, he noticed that the forest around him was starting to change. The trees were getting taller and thicker, and the air was starting to feel cooler and damper. He knew he was getting closer to the heart of the forest, and that meant he was getting closer to the golden acorn.

But he also knew that it meant he was getting closer to the creature that had been chasing him. He could feel its presence nearby, watching and waiting for the right moment to strike. He knew he had to be careful, to stay alert and ready for anything.

Finally, he reached a clearing in the forest, and there he saw the golden acorn, shining brightly in the center. It was guarded by a circle of glowing mushrooms, and Tom knew that this was the final challenge he had to overcome in order to claim the reward.

But as he stepped into the clearing, the creature emerged from the shadows, its eyes glowing with malice. Tom knew that this was it, the final showdown. He steeled himself for the fight, knowing that he had to be brave and strong if he wanted to survive.

The creature lunged at him, its claws extended and ready to strike. But Tom was ready, and he dodged out of the way, narrowly avoiding the creature's attack. He picked up a nearby branch and

Describe the fight in details between Tom and the creature.

Tom picked up a nearby branch and swung it at the creature, trying to keep it at bay. The creature snarled and lunged at him again, but Tom was ready for it. He dodged and weaved, using his speed and agility to his advantage.

The creature was powerful, but Tom was determined. He fought with all his might, using every trick and strategy he could think of to keep the creature at bay. He could feel his strength and skill improving with each passing moment, and he knew that he was starting to gain the upper hand.

The creature stumbled and fell, and Tom saw his opportunity. He leapt forward and grabbed the golden acorn, holding it triumphantly in the air. The creature snarled in anger and frustration, but it knew that it was beaten.

Tom grinned, feeling a surge of pride and victory. He had succeeded in the challenge, and he had proved himself worthy of the golden acorn. He turned to leave the clearing, ready to find Jack and Luna and share the good news.

But as he stepped out of the clearing, he heard a voice calling to him. It was Luna, its silver body shining in the dim light. "Tom, you did it!" it cried, its voice full of excitement and admiration.

Tom grinned, relief and happiness flooding through him. "I couldn't have done it without you, Luna," he said, giving the creature a hug.

"And me!"

Describe the reunion between the 3 characters. Don't rush.

Tom and Luna were joined by Jack, who had also managed to escape from the creature. The three of them hugged and celebrated, relief and happiness flooding through them.

"We did it!" Jack cried, his face alight with excitement. "We survived the dark forest and retrieved the golden acorn!"

"We couldn't have done it without each other," Tom said, giving his friends a grateful smile. "We make a pretty good team."

Luna nodded, its eyes shining with pride. "You have proven yourselves to be brave and worthy," it said. "You have earned the right to the golden acorn's reward."

Tom and Jack looked at each other, anticipation and curiosity filling their hearts. What could the golden acorn's reward be? They had no idea, but they knew that they would find out soon enough.

With Luna leading the way, they made their way back to the edge of the forest, eager to claim their prize and return home. They had faced many dangers and challenges, but they had come out on top, stronger and wiser than they had been before.

They emerged from the forest, triumphant and victorious, ready to face whatever challenges came their way in the future.

Now that Tom and Jack exists the dark forest, write the scene where they say goodbye to Luna.

As Tom and Jack emerged from the dark forest, they were greeted by the sight of the sun setting on the horizon, casting a warm, golden glow over the landscape. They breathed in the fresh air, grateful to be out of the dark, dangerous forest.

"We did it," Jack said, a smile spreading across his face. "We survived the dark forest and retrieved the golden acorn."

Tom nodded, a sense of pride and accomplishment filling him. "We couldn't have done it without Luna," he said, looking back at the forest. "I wonder if we'll ever see it again."

Luna, who had been following them, stepped out of the shadows, its silver body shining in the dim light. "I must return to the forest," it said, its voice soft and melodic. "But I will never forget you, Tom and Jack. You are brave and worthy, and I am proud to have been a part of your journey."

Tom and Jack hugged Luna, tears of gratitude and sadness filling their eyes. They knew that this was goodbye, but they also knew that they would never forget Luna and the adventure they had shared.

"Thank you, Luna," Tom said, his voice choked with emotion. "Thank you for everything."

Luna smiled, its eyes shining with warmth and kindness. "You are welcome," it said. "Farewell, Tom and Jack. May your lives be filled with adventure and wonder."

With that, Luna turned and disappeared back into the dark forest, leaving Tom and Jack to continue on their journey. They watched it go, their hearts full of gratitude and sadness, knowing that they had gained a friend for life.

What happens next.

With Luna gone, Tom and Jack continued on their journey, eager to claim the golden acorn's reward and return home. They made their way through the forest, their hearts filled with excitement and anticipation.

As they walked, they talked about their adventure, reliving every moment and discussing all the things they had learned. They laughed and joked, their bond stronger than ever, and they felt like they could conquer anything.

Finally, they reached the edge of the forest, and there they saw a beautiful meadow, filled with flowers and sunshine. In the center of the meadow was a large, golden tree, its leaves shining like diamonds in the sunlight.

Tom and Jack knew that this was it, the final destination of their journey. They walked towards the tree, their hearts pounding with excitement and anticipation.

As they reached the tree, a voice spoke to them, its tone gentle and wise. "Tom and Jack," it said. "You have proven yourselves to be brave and worthy. You have survived the dark forest and retrieved the golden acorn. You have earned the right to the golden acorn's reward."

Tom and Jack looked at each other, their eyes shining with wonder. "What is the reward?" they asked, their voices filled with curiosity.

"The reward is the knowledge and power of the golden acorn," the voice said. "It will give you the ability to control and manipulate the forest, to protect it and keep it safe from harm. You will be the new guardians of the dark forest, and it will be your duty to keep it safe and healthy for generations to come."

Tom and Jack were overwhelmed by the magnitude of the reward. They looked at each other, their hearts filled with gratitude and awe. "Thank you," they said, bowing their heads in respect.

"You are welcome," the voice said. "Use your knowledge and power wisely, Tom and Jack. And remember, the forest is always with you, watching and guiding you on your journey."

With that, the voice fell silent, and Tom and Jack were left standing in the meadow, the golden acorn in their hands. They looked at each other, their hearts full of wonder and excitement, knowing that their lives would never be the same again. They had embarked on a journey, and they had emerged as the new guardians of the dark forest, ready to face whatever challenges came their way.

Write about how Tom and Jack use their new power to help their new friend Luna.

Tom and Jack were amazed by the power and knowledge of the golden acorn. They spent many hours studying and learning, exploring the full extent of their new abilities. And as they learned, they realized that they could use their powers to help their new friend, Luna.

Luna had returned to the dark forest, but it was not safe. The evil creature that had chased them was still there, lurking in the shadows and causing trouble. Luna was brave and strong, but it could not fight the creature alone.

Tom and Jack decided to use their powers to help Luna. They used their knowledge of the forest to create traps and obstacles, making it difficult for the creature to move freely. They also used their powers to control the plants and animals of the forest, creating an army of allies to help them in their fight.

And finally, when the creature was at its weakest, Tom and Jack launched their final attack. They used their powers to control the very elements of the forest, creating a storm of wind and rain that battered the creature, weakening it even further.

In the end, the creature was defeated, and Luna was safe. Tom and Jack were hailed as heroes, and Luna was grateful for their help. The dark forest was once again at peace, and Tom and Jack were proud of their new roles as guardians of the forest.

They continued to use their powers to help Luna and the other inhabitants of the forest, and they knew that they would always be there to protect and defend their new home. They had found a place where they belonged, and they were happy and content.

Write a synopsis of the story we just created, as if it was the fourth cover of the book. Do not reveal too much spoilers. Also, find a title for the story.

Title: The Guardians of the Dark Forest

Tom and Jack are two ordinary teenagers, enjoying a sunny Sunday afternoon by bicycling in the woods. But when they stumble upon a mysterious golden acorn, they are drawn into a dangerous and exciting adventure.

With the help of their new friend, Luna, they must brave the dark forest and overcome many challenges in order to claim the golden acorn's reward. They face fierce creatures and treacherous obstacles, but they never give up, using their courage and determination to succeed.

In the end, Tom and Jack emerge victorious, having proven themselves to be brave and worthy. They are rewarded with the knowledge and power of the golden acorn, becoming the new guardians of the dark forest. They use their powers to protect their new home and its inhabitants, including Luna, who is grateful for their help.

The Guardians of the Dark Forest is a thrilling tale of adventure, friendship, and the power of determination. Follow Tom and Jack as they embark on a journey of self-discovery and become the heroes they never knew they could be.

Rewrite the synopsis, but without revealing the conclusion.

Title: The Guardians of the Dark Forest

Tom and Jack are two ordinary teenagers, enjoying a sunny Sunday afternoon by biking in the woods. But when they stumble upon a mysterious golden acorn, they are drawn into a dangerous and exciting adventure.

Follow Tom and Jack on their journey of self-discovery as they become the heroes they never knew they could be. The Guardians of the Dark Forest is a thrilling tale of adventure, friendship, and the power of determination.

Nucléaire, Stop ou Encore ? (Antoine de Ravignan, 2022)

2022-11-13T00:00:00Z

Ce livre explore la question de l'énergie nucléaire, et plus particulièrement celle de l'énergie nucléaire en France, laquelle se repose sur le nucléaire pour 70% de son électricité. Une exception dans le monde, qui est due à un développement extraordinaire dans les années 80. Spoiler alert : à la question posée dans le titre, le livre répond "Stop".

J'ai trouvé le livre extrêmement bien documenté. Toutes les notions techniques relatives au fonctionnement du nucléaire correspondent à ce que j'avais déjà pu lire sur le sujet précédemment (sujet auquel je m'étais intéressé après avoir vu la série Chernobyl). Les faits et les enjeux sociétaux concernant l'énergie correspondent à ce que j'ai pu lire ou entendre sur le sujet ailleurs. Toutes les assertions du livre sont vérifiables via pléthore de références en notes de bas de page. Bien que je n'ai pas la prétention d'être moi-même expert sur le sujet, j'ai l'impression qu'on est sur un travail très sérieux de quelqu'un qui maîtrise le sujet. J'ai appris pas mal de choses.

Le sérieux de cette accumulation de faits étant admis, c'est donc dans la mise en lumière de ces faits, leur interprétation, et les jugements à émettre à partir de là, que réside la marge de manœuvre qui permet d'être d'accord ou pas avec le raisonnement de l'auteur.

Ce raisonnement est articulé en trois grandes phases : premièrement, la présentation des défauts du nucléaire afin de montrer que ça n'est pas une énergie satisfaisante ; deuxièmement, l'explication selon laquelle le déploiement massif du renouvelable sera nécessaire dans le mix énergétique, au moins en accompagnement du nucléaire ; troisièmement, la justification qu'un mix quasi-intégralement renouvelable (voire 100% renouvelable) est envisageable.

Au-delà des contre-arguments qu'on peut apporter aux détails individuels du raisonnement, le livre souffre selon moi d'une faiblesse structurelle : il compare une énergie qui est déjà en place à l'échelle (le nucléaire) et y trouve de nombreux défauts à cause des diables dans les détails de l'exploitation, à une énergie (les renouvelables) qui n'a jamais été mise en place à l'échelle, dont la capacité à être exploitée à l'échelle reste donc entièrement théorique, et dont on ne saurait trouver les défauts de l'exploitation en pratique, puisque exploitation, il n'y a pas.

Cela ne signifie ni que le nucléaire est satisfaisant, ni que les renouvelables ne peuvent pas fonctionner, mais simplement que le raisonnement est biaisé. Le moteur de ce biais est la confiance bien trop cavalière que l'auteur accorde aux études théoriques des différentes organisations qui publient des scénarios sur la faisabilité de telle ou telle solution. "La démonstration [d'un mix haut-renouvelable] en a largement été faite. [...] Pas seulement par des experts engagés en faveur d'une sortie de l'atome mais aussi par des institutions publiques qu'on ne peut dire partisanes et dont aucun ingénieur et économiste sérieux ne saurait contester la robustesse des analyses." C'est donc sur cet argument d'autorité qu'on devrait accepter comme acquise l'analyse, sans pouvoir la contester sous peine de ne pas être sérieux ! (Il existe des gens suffisamment sérieux pour être auditionnés à l'Assemblée Nationale qui contestent précisément ces analyses.)

La petite phrase précédente est d'autant plus choquante venant du livre, car ce dernier défend au demeurant la nécessité d'un débat citoyen éclairé, et non pas l'accaparation du sujet par des experts technocrates qui prendraient des décisions dans leur coin sans que personne ne comprenne ce qui se passe. L'auteur souligne que cette soif de technocratie est habituellement l'apanage des pro-nucléaires, qui se considèrent dans le camps des "rationnels", mais il faudrait donc faire bien attention à ne pas basculer dans ce même écueil lorsqu'on parle du renouvelable en évoquant les études qui "démontrent" et dont "on ne saurait contester la robustesse".

Dans le reste de cet article je reviens sur les trois grandes parties de l'argumentation, et pour chacune d'entre elles, j'équilibre avec les contrepoints et les doutes qui me sont venus à l'esprit.

Le nucléaire n'est pas satisfaisant

Le nucléaire est cher

La première remarque que fait l'auteur est que le nucléaire n'est pas une énergie qui se développe de manière massive dans le monde, pourvu qu'elle soit pilotable et non émettrice de CO₂ (qui sont les deux qualités essentielles recherchées pour répondre au réchauffement climatique). C'est le coût des centrales qui est identifié comme le point bloquant. Une centrale nucléaire est un projet colossal, qui est non seulement très long à mener à terme, mais aussi très long à rembourser via son exploitation une fois terminée.

La situation de la France dans les années 80 est donc identifiée comme une exception au cours de laquelle les étoiles géo-politiques et financières se sont alignées, phénomène sur lequel aucun autre pays (ni même la France des années 2020) ne peut vraiment compter. Sous la pression de décarboner leur production d'énergie, c'est donc simplement par manque de moyens que de nombreux pays se tournent vers les énergies renouvelables, qui sont largement plus accessibles, même si elles ne sont pas pilotables (et nécessitent donc des énergies fossiles pour combler les trous de production).

Même si ces pays tentaient leur chance avec le nucléaire, les projets industriels nucléaires sont tellement enclins à souffrir de development hell, que le succès n'est pas garanti, et que les délais peuvent atteindre de tels ordres de grandeur qu'ils commencent à être non négligeables par rapport au calendrier des objectifs de décarbonisation.

Cela est particulièrement vrai pour les têtes de séries, comme le réacteur Flammanville-3 (tête de série de l'EPR en France) dont la construction a commencé en 2007 et qui, initialement prévue pour 5 ans, n'est toujours pas terminée, et ne devrait pas se terminer avant fin 2023, malgré les compromis qui ont été fait sur la sûreté par rapport à la conception initiale.

Contrepoints

Dans le dernier chapitre du livre, lorsque l'auteur parle du fonctionnement d'un mix fort en renouvelable, il explique que, à partir du moment où le renouvelable dépasse 35% de la production, les adaptations à faire sur l'infrastructure électrique du pays induisent un coût significatif, comparable aux coûts du nucléaire. Cela semble donc auto-détruire cet argument du début du livre : les pays qui ne seraient pas capables de faire du nucléaire à l'échelle finiraient par se rendre compte qu'ils ne peuvent pas non plus faire du renouvelable à l'échelle. (Cela dit, 35% de renouvelables sont toujours déjà préférables à 35% de sources fossiles.)
Le livre passe tranquillement la Chine et l'Inde sous le tapis comme étant des "exceptions" qui investissent dans le nucléaire. Ces "exceptions" sont respectivement les premiers et troisièmes producteurs d'électricité dans le monde, et représentent à eux deux 38% de la production mondiale. (Cela dit, ils investissent aussi énormément dans les énergies renouvelables.)
Cette partie du livre m'a fait penser à la vidéo The Economics of Nuclear Energy, que je recommande. Cette vidéo met notamment en lumière le fait que le nucléaire est certes un investissement risqué et massif, mais très lucratif une fois qu'il est en rythme de croisière. La raison pour laquelle ces investissements sont si durs à initier est avant tout le court-termisme politique, qui rend fondamentalement difficiles les investissements dont l'horizon dépasse largement la durée d'un mandat.

Les difficultés à faire du nucléaire mettent une pression pour des compromis sur la sûreté

C'est le propre de tout projet compliqué et en retard que de faire des compromis, et ces compromis sont typiquement fait sur la sûreté. L'industrie nucléaire, malgré l'image sophistiquée qu'on puisse s'en faire, n'est pas exclue par ce phénomène. En France, l'Autorité de Sûreté Nucléaire (ASN) est l'organisme indépendant qui surveille le niveau de sûreté du nucléaire. Le livre plonge dans le détail des dossiers afin de montrer à quel point la sûreté nucléaire est un éternel jeu de négociations entre l'État, l'ASN, et EDF. J'étais déjà au courant de la non-perfection de la sûreté du nucléaire via un épisode des Pieds sur Terre, dans lequel un employé d'EDF explique comment il a été contraint de falsifier des données à propos de la centrale de Tricastin afin de cacher des informations à l'ASN, ce qui noirci encore plus le tableau.

L'accident à éviter à tout prix dans un réacteur nucléaire est la fusion du cœur. Fusion au sens chimique : l'assemblage d'uranium et tout ce qu'il y a autour passe à l'état d'un magma (le corium) extrêmement radioactif. Dans ces conditions, il n'y a plus de garantie sur l'absence de rejet de radioactivité dans l'environnement. Premièrement parce que dans le cadre d'un tel accident il est vraisemblable que l'enceinte de confinement ne soit plus totalement étanche (euphémisme dans certains cas), et deuxièmement parce que si de la pression s'accumule dans l'enceinte de confinement, il peut être préférable de volontairement laisser s'échapper de la matière (dont radioactivité) afin d'éviter une rupture complète.

Le réacteur est donc constamment refroidi à l'eau afin qu'il n'entre pas en fusion. En cas de coupure d'électricité (ce qui, a priori, désactiverait les pompes à eau), des barres de contrôle (qui ont pour vertu de capturer les neutrons et mettent donc donc un terme aux réactions de fissions) s'insèrent dans le cœur pour immédiatement arrêter son activité. Il s'agit d'un système passif : les barres sont tenues en l'air par l'électricité, elles tombent par gravité dans le cœur en absence d'électricité. Cependant, même une fois éteint, le cœur continue de dégager une chaleur non négligeable à cause de la radioactivité des produits de fission, chaleur suffisante pour le faire fondre au bout de quelques heures. Des générateurs de secours doivent donc prendre le relai pour continuer à pomper l'eau et refroidir le cœur.

Parmi les exemples qui illustrent que le nucléaire est loin d'être d'une sûreté invincible, il y a la géographie de la centrale de Tricastin : cette dernière est construite en contrebas du canal qui l'alimente en eau, si bien que la rupture de la digue du canal (à cause d'un séisme ou de toute autre raison) inonderait la centrale, ce qui pourrait entraîner la perte du refroidissement des réacteurs. Malgré que la centrale tourne depuis 1980 et que l'IRSN avait déjà lancé des alertes en 2007, ce n'est qu'en août 2017 que EDF remonte officiellement une alerte à l'ASN. Cette dernière ordonne l'arrêt de la centrale un mois plus tard, tant que la digue n'a pas été renforcée pour résister à un séisme (travaux que EDF a réalisé dans les 3 mois qui ont suivis 😌).

Parmi les exemples qui montrent le type de négociations qui peuvent avoir lieu entre l'état, l'ASN, et les acteurs industriels du nucléaire, il y a la cuve du réacteur de Flamanville en construction. Cette dernière a été livrée en 2013 après 7 ans de construction, pour que Areva détecte en 2014 que la composition chimique n'est pas aux normes. L'ASN, ayant obtenue cette information, interdit la mise en service de cette cuve en l'état. Le gouvernement rentre en jeu en 2015, en publiant un décret qui "autorise l'ASN à autoriser" sous réserve qu'Areva effectue des tests afin de démontrer que la cuve, en l'état, et sûre. Cette démonstration a lieu 2 ans plus tard, lorsque Areva présente les résultats d'essais de sûreté à l'ASN. Sauf qu'entre temps la cuve a déjà été installée dans le réacteur, rendant impossible le remplacement de son fond, si tant est que les résultats des essais l'auraient nécessité. (L'ASN a autorisé la mise en service de la cuve, sous réserve de "sa surveillance".)

Ces enjeux sont d'autant plus cruciaux pour le parc actuel, dont les installations sont vieillissantes. Les centrales du parc sont conçues pour fonctionner pendant 40 ans, et vont donc toutes arriver à expiration dans les années 2020 et 2030. Puisque nous n'avons pas la capacité de toutes les remplacer à temps, il va falloir les prolonger. Le standard défini par l'ASN pour prolonger une centrale consiste à mettre à jour un certains nombre de ses composants pour les rendre aussi fiables que ceux des réacteurs de dernière génération. Mais puisque nous n'avons pas non plus la capacité d'effectuer ces mises à jour (qui nécessitent l'arrêt de la centrale) tout en maintenant notre capacité de production, il faut aussi repousser l'échéance de ces mises à jour. Au final, le calendrier des mises à jour s'échelonne jusqu'à 48 ans de fonctionnement sans mise à jour pour certaines centrales.

Face au risque d'accident, l'auteur cite quelques estimations de probabilité d'un accident nucléaire, généralement très faibles, qu'il écarte d'un revers de la main, puisqu'elles sont basées sur des hypothèses inconnues. Le directeur de l'ASN lui-même a dit devant le Sénat que personne ne peut prétendre qu'un accident nucléaire n'est pas possible.

Je suis sensibilisé depuis que j'ai lu Antifragile à l'inutilité des calculs de risques de type high-impact low-probability (de tels calculs sont en principe simplement faux). La seule chose à faire est de partir du principe que le pire des cas arrivera et de minimiser son exposition à une telle occurrence (The predictors' reply when we point out their failures has typically been "we need better computation" in order to predict the event better and figure out the probabilities, instead of the vastly more effective "modify you expose" and learn to get out of trouble). Dans le cas du nucléaire, il me semble que c'est l'inconnue du "pire des cas" qui rend la question compliquée.

Contrepoints

Il semble logique que les choses qui font l'objet d'une observation minutieuse sont précisément les choses qui souffriront du plus de "dossiers". Bien que l'accumulation d’anecdotes par l'auteur dans cette partie du livre dresse un tableau a priori accablant du nucléaire, c'est avant tout le signal que l'ASN fait très bien son travail et que cette industrie est très fortement surveillée. Elle est vraisemblablement d'un niveau de sécurité très avancé. (Mais c'est peut-être le strict minimum pour une industrie de cette nature, qui partirait en vrille au moindre relâchement.)
L'accident à éviter à tout prix selon l'auteur est un accident de type Fukushima. Sauf que les pro-nucléaires sont blasés de Fukushima, essentiellement dû à la quantité inoffensive de radioactivité lâchée dans l'environnement. L'auteur pointe du doigt les conséquences politiques (un accident donne une incitation forte aux politiciens, face à l'opinion publique, d'arrêter les centrales, alors remplacées par les énergies fossiles) et financières (200 milliards d'euros pour le seul démantèlement de la centrale), mais soyons honnête, c'est bien la radioactivité qui fout la merde. C'est à ce titre que le "pire des cas" mériterait d'être discuté. Ma compréhension en l'état de cette question est qu'en cas d'accident nucléaire, "shit's fucked up yo", et qu'il est difficile de garantir une borne supérieure sur la quantité d'émissions dans l'environnement (c'est pour ça que je ne suis pas convaincu des discours rassurants pro-nucléaires).

Les déchets sont complexes à gérer

L'uranium se présente dans la nature sous la forme de 2 principaux isotopes : U-238 (99.27%) et U-235 (0.72%). Seul U-235 est fissile, et c'est donc celui qui est intéressant pour une centrale nucléaire. Pour cette raison, les minerais d'uranium passent d'abord par une étape d'enrichissement, c'est-à-dire que la teneur en U-235 par quantité de matière est augmentée. Pour le nucléaire civil, il est suffisant d'enrichir l'uranium à hauteur de 4% : le combustible présent dans un réacteur nucléaire contient 4% d'isotopes U-235.

Lors du fonctionnement du réacteur, ce combustible va donner vie à de nouveaux isotopes :

Les produits de fission, qui sont le résultat des noyaux d'uranium qui ont fissionnés en plus petits éléments. Krypton, barium, césium, sont des exemples de tels éléments. Ils sont très radioactifs.
Les actinides, qui sont des noyaux qui ont capturé des neutrons et ont muté en d'autres éléments. On peut les séparer en deux catégories :
- Les actinides "mineurs" (e.g. Neptunium) qui sont inutilisables et très radioactifs.
- Le plutonium, dont une partie est recyclable (pas seulement pour les armes nucléaires, mais aussi pour le civil).

Une fois qu'un réacteur a effectué un cycle et que le combustible est changé, le combustible usé contient :

96% d'uranium appauvri, essentiellement non fissile (puisqu'une grande partie des isotopes U-235 ont fissionnés), mais dans lequel il reste tout de même des isotopes fissiles.
3% de produits de fission et d'actinides mineurs.
1% de plutonium.

La plupart des pays décident de tout considérer comme des déchets, mais la France et la Russie s'inscrivent en exception, car ils recyclent l'uranium (qui peut être ré-enrichi) et le plutonium (pour être utilisé dans les réacteurs de type MOX, et potentiellement un jour dans les réacteurs à neutron rapide).

Le livre critique le fait que la France se targue de "recycler" 97% du combustible usé (et donc de réduire les déchets) lorsqu'une bonne partie de ce dernier se retrouve ni recyclé ni enfoui, mais simplement entreposé. La doctrine est en effet que toute matière radioactive qui pourra avoir un usage utile n'est pas un déchet. Ainsi la France stocke actuellement 318 000 tonnes de métaux lourds radioactifs (uranium appauvri et plutonium), dont le recyclage est tout à fait théorique, si bien que l'ASN considère depuis 2020 qu'il s'agit en partie de déchets.

En ce qui concerne les 3% de déchets hautement radioactifs, ils sont vitrifiés dans des fûts en acier inoxydable. Cependant, avant d'en arriver là, ils doivent être refroidis en piscine de désactivation, d'abord dans la centrale elle-même, puis dans l'usine de retraitement de La Hague. Non seulement les risques liés à l'interruption de refroidissements du cœur du réacteur s'appliquent aussi aux déchets en cours de refroidissement, mais ces piscines constituent un goulot d'étranglement sur le chemin du traitement, qui est donc un élément en plus susceptible d'appliquer une pression pour des compromis sur la sûreté.

Contrepoints

Le contrepoint principal aux remarques alarmistes à propos des déchets nucléaire réside essentiellement dans le fait que leur toxicité nucléaire, bien qu'à ne pas prendre à la légère, n'a pas pour autant l'exclusivité de la dangerosité en comparaison de la toxicité chimique des déchets de toute autre industrie. En l'occurrence, leur surveillance accrue amène le même contrepoint que celui de la section précédente : c'est là où on surveille le mieux qu'on trouvera le plus de défauts.

Le renouvelable sera nécessaire pour au moins accompagner le nucléaire

Pour cette partie, l'auteur se repose sur des études de différentes organisations, en particuliers: négaWatt, l'Adem, et RTE. Le principe de ces études est ce concevoir des scénarios qui permettraient à la France d'atteindre la neutralité carbone en 2050. Les différents scénarios donnent différentes trajectoires possibles sur le mix énergétiques (de 100% nucléaire à 100% renouvelables en passant par les intermédiaires) et dressent les hypothèses qui permettent ou non d'utiliser telle trajectoire.

Le point de départ des raisonnements consiste à regarder la part de l'électricité dans la consommation finale d'énergie du pays : en France, 25% de l'énergie finale consommée provient de l'électricité (chauffage, lumière, machines électriques), et les 75% restants d'autres sources, la grande majorité d'entre elles étant émettrices de CO₂ (transport, industries, machines thermiques, etc). Ainsi, la question de l'électricité est loin de suffire à résoudre le problème des gaz à effet de serre, puisqu'elle n'influe que sur le quart de ce problème.

Il existe des solutions permettant de décarboner les 3 quarts restants, telles que la biomasse ou l'électrification des procédés (à supposer que la source d'électricité soit verte), mais ces solutions ont une vitesse de mise en place très faible, et il ne faudra pas compter dessus pour atteindre la neutralité carbone. C'est pour cette raison que toutes les études s'accordent sur un point : le seul moyen d'atteindre les objectifs est de diminuer la consommation totale. Pour cela, il faut d'une part améliorer l'efficacité (produire autant de choses mais en utilisant moins d'énergie), et d'autre part simplement consommer moins : la sobriété.

En partant du principe que l'efficacité et la sobriété ne pourront pas être poussées à l'infini et qu'il restera donc toujours pas mal de puissance à générer, les études misent donc tout de même sur une certaine avancée de l'électrification des 75% restants (parmi d'autres solutions). Par exemple, l'une des études donne le chiffre de 55% de l'énergie finale provenant de l'électricité en 2050. Pourcentage sur un total censé être certes plus petit, mais qui correspond tout de même à une valeur absolue nettement supérieure à la quantité d'électricité produite aujourd'hui. En bref, il faut imaginer qu'en 2050 on devra produire largement plus d'électricité qu'aujourd'hui.

C'est là que le raisonnement reboucle avec les défauts du nucléaire pré-établis : compte tenu des grandes difficultés à remplacer le parc nucléaire actuel (et donc à juste maintenir la puissance actuelle), il semble invraisemblable de penser que le nucléaire seul serait capable d'assumer une augmentation significative de la puissance demandée. Par exemple, dans le rapport de RTE, le scénario qui maximise la part du nucléaire dans le mix est basé sur un rythme effréné de constructions de réacteurs, que EDF considère comme son maximum théoriquement faisable mais qui 1/ n'a pas été décidé en l'état et 2/ ne serait probablement pas atteignable en pratique quand bien même il serait décidé.

Dans une telle situation, en l'absence d'investissements sur le renouvelable, les solutions restantes pour répondre à la demande serait de : prolonger abusivement le parc existant (dangereux, et insuffisant) ; faire brûler des bons vieux fossiles (le problème qu'on cherche à résoudre).

Selon le livre, ce principe est en fait déjà une réalité, puisque les renouvelables se substituent déjà en partie aux énergies fossiles lorsque le nucléaire n'est pas capable d'assumer la demande pendant l'arrêt des réacteurs pour la grande phase de maintenance pour la prolongation du parc.

Contrepoints

Mon principal doute à propos de ce raisonnement concerne l'étape où les calculs se mettent à supposer une forte électrification des 75% d'énergie actuellement non électrique. Cette hypothèse est faite par nécessité du raisonnement à partir du moment où on limite l'hypothèse de la sobriété, mais elle nécessite en pratique que cette grande électrification puisse bel et bien avoir lieu sur le plan technologique, et le livre admet lui-même que ce processus est très lent, et qu'on ne peut que modérément compter dessus.

À quoi bon donc élaborer une grande vision de l'industrie électrique, qu'elle soit nucléaire ou renouvelable, si on n'est même pas sûrs qu'il y aura des machines prêtes à consommer à l'autre bout du câble ? Tout ce raisonnement n'est-il pas un déni de la constatation que la seule solution sûre de fonctionner, et sur laquelle nous avons le contrôle (contrairement à un deus ex machina technologique) est la sobriété ?

Dans certains débats, le sujet est présenté sous la forme de la corrélation entre la croissance économique (= faire tourner des machines) et les émissions de CO₂, et la croyance selon laquelle nous arriverons à découpler ces 2 courbes (= faire tourner des machines sans émissions) n'est pas partagée par tous.

Un mix haut-renouvelable est envisageable

Je vais avoir du mal à résumer cette partie, que j'ai trouvée confuse, et abrutissante de chiffres en tous genres. Ça parle de stocker de l'énergie à coup de pompage-turbinage ou d'hydrogène. Ça parle de mise à jour de la grille électrique (très coûteuse) pour prendre en compte intermittence des sources. Et j'ai l'impression que ça se résume à "vous inquiétez pas les pros ont fait les calculs ça marche."

Le contrepoint de cette partie est celui que j'ai écrit en introduction : tout cela est entièrement théorique et, en l'occurrence, cette partie du livre n'a pas réussie à me convaincre (ni-même à me vulgariser) la théorie. 🤷

Conclusion

Je n'ai pas de grande conviction idéologique à la sortie de ce livre, mais juste quelques éléments de pensée :

Peu importe la place qu'on lui donne dans le mix, le nucléaire est loin d'être une énergie parfaite.
Peu importe le place qu'on leur donne dans le mix, les énergies renouvelables sont les seules sources autres que le nucléaire qui n'émettent pas de CO₂, et sont donc ce qui nous resterait dans le cas où le nucléaire nous lâcherait pour une raison ou une autre.
Peu importe le mix, il faut consommer moins.
La conception du mix est avant tout un exercice de prédiction du futur, et toute proposition doit donc être étudiée avec précaution et sans illusion de certitude.

Relativity: The Special and the General Theory (Albert Einstein, 1916)

2022-09-30T00:00:00Z

This book was written by Einstein just one year after having published his paper about the general theory of relativity (1915) and 11 years after having published his theory of special relativity (1905). The goal of the book is to explain in simple terms his theories for people who don't have a strong background in maths/physics, but still some basic notions[1]. It's a relatively small book (180 pages). I read the French translation which was published in 1956.

[1] The fourth cover of my French edition recommends a level of baccalauréat, which is the French exam to validate high school (I assume with a scientific specialty).

I struggled to understand many of the concepts in the book. Particularly, I failed to get a holistic view of the general theory of relativity, which is significantly more advanced, conceptually and mathematically, than the special one. I guess I shouldn't shy too much from my apparent lack of intelligence, as my understanding (from Wikipedia) is that the general theory of relativity wasn't well understood by the scientific community itself before decades after this book was published.

Still, I found that there was value in the book because of the following: understanding a gross outline of what those theories are and how they work; going through a lot of funny thoughts experiments, which Einstein seemed to love; peeking into Einstein's intellectual process in finding the theories.

Outline of the theories

Special relativity

The principle of relativity stipulates that the laws of Nature should work exactly the same in different frames of reference. For example it shouldn't matter whether you're at a fixed point on the ground or traveling on a train, from your point of view, everything you observe should behave according to the same laws.

One of those laws is that light travels at constant speed in a void.

This immediately presents a paradox, because if you observe a ray of light traveling at speed c from the ground, then someone traveling in a train in the same direction than this ray of light is expected to measure its speed as c minus the speed of the train, which would mean that either the principle of relativity doesn't hold, either the constancy of the speed of light isn't a fundamental law of Nature.

Since none of those options are satisfactory, Einstein prefers altering the notion of speed itself: the special theory of relativity stipulates that distances and time aren't the same in the different frames of reference. There even is an exact formula to convert them from one frame to another: the Lorentz transformation.

When you put the speed of light in those transformations, you realize it stays constant, which means that this is a model in which both the principle of relativity and the constancy of speed of light hold, so it's a good model, I guess.

General relativity

The problem with everything above is that it only works with inertial frames of reference, which means frames of reference that move at constant speed in the same direction; they don't accelerate and they don't rotate on themselves. This is what is "special" in the special theory of relativity: it only solves the problem for a very specific kind of frames of reference.

The general theory of relativity, as you can guess, tries to make the principle of relativity work for all kinds of frames of reference, no matter whether they accelerate, rotate, jump around, dance the mambo, or anything else. This is where shit gets serious.

If the train you're in starts braking (it isn't an inertial frame of reference anymore), then from your point of view there is a force pulling you to the front of the train (one of the so-called "inertial forces" when you deal with non-inertial frames of reference in Newtonian mechanics). According to the principle of relativity, the laws of Nature should be the same in all frames of reference, which means that this force should be a fundamental manifestation of Nature. Well, Einstein decides it's ✨ gravity ✨

Now, this is where my understand starts being blurry: I'm not sure we are supposed to interpret this as if actual real gravity appeared out of nowhere in the train to pull you forward. Rather, it should mean that from your point of view in the train, there is no observable difference between assuming you are pulled by an inertial force or pulled by gravity. This is the equivalence principle.

Things get interesting when you mix the equivalence principle with light. Imagine you are in a spaceship that is accelerating in space. Since it is accelerating, you are pushed to the bottom of the ship, which, according to the principle of equivalence, is exactly the same as living in a gravity of some amount. Now, imagine that a straight ray of light is passing through a window of the ship (we assume no refraction). Viewed from space, the ray is straight, but viewed from the interior of the ship, it is curved (since the ship is accelerating). Well, this is where the principle of equivalence starts getting real: it is observed that when a ray of light passes by a massive object generating actual gravity, it is curved, in the exact same way than in the accelerating spaceship.

We can also apply the principle of equivalence to time. Imagine a carousel on which you put 2 clocks: one at the center, and one at the edge. From the frame of reference of the carousel, the clock at the center is not experiencing any particular force. However, the clock at the edge is experiencing some force that is trying to pull it away from the carousel (the centrifugal force). According to the equivalence principle, this means that the clock at the edge is subjected to some form of gravity. Furthermore, because of the principles of special relativity, since the clock at the edge is moving but not the clock at the center, the two clocks aren't experiencing the same time. This means that there is a link between gravity and time. Again, the principle of equivalence really works, since massive bodies, which generate a lot of gravity, alter the flow of time, exactly in the way that would be expected on this carousel.

Beyond those fine examples, the book goes on to explain how the entire general theory of relativity holds together (the way the Lorentz transformations make the special relativity hold together), at which point I failed to understand most of what I was reading.

Experimental verification

From what I've read, the theory has been confirmed again and again by a multitude of experiments throughout the XXth century, but here I'm listing the two early confirmations that are given in the book:

It can be measured that Mercury exact orbit around the Sun doesn't obey Newtonian mechanics, but obeys relativist mechanics.
It can be measured that the Sun deflects the light from distant stars, deflection which is explained by relativity.

Einstein also describes a third consequence of the theory: gravitational redshift (which I didn't take the time to try to understand quite well), but he explains in the book that astronomers were still working hard to try to actually observe it (it was first observed in 1925, nine years later).

Einstein intellectual process

Since the book is written in bottom-up way, and early after the publication of the theories, it sorts of opens a window into Einstein's mind on how he came up with those theories. Einstein usually starts by introducing a clever thought experiment that showcases some paradoxical stuff about Nature, and then, using some form of intuitive judgment of how it could make sense, he works his way up to a theoretical idea.

I found it refreshing how much of a physics book it is. When I studied physics in prépa, it was all formulas and diagrams and it was very easy to forget that you're supposed to be reasoning about the real world and not some arbitrary abstraction. Einstein, to the contrary, never let physics go out of sight.

What is surprising, however, is that since the manifestations of the theory only happen in extremes conditions (speeds close to the speed of light, extremely massive objects), he had very little actual physics to depend on, but still succeeded in developing the theory to a high level of sophistication, adding details and texture to it, always depending on his thought experiments. This reminded me of the way Waymo or Tesla are training their autonomous cars in software simulations more than on real roads. The man didn't have access to actual physics, so he fabricated the theory by simulating the Universe in his damn mind.

The best don't even try hard

2022-07-10T00:00:00Z

The more I read books about elite people (people having world-class success in what they do), the more I'm under the impression that they don't even try that hard about what they do; they just work naturally very hard and very effectively, and they happen to be so good that they reach the level they're at. This seems important to me, as it mostly eliminates the whole "motivational" and "surpassing yourself" bullshit when talking about success. It seems to me that if you feel that you need motivation, then you have already lost.

The best example I know is how Richard Feynman has always been very nonchalent about being a world-class physicist. He truly did not consider himself particularly special.

The recipe for success seems to be the following:

Have a subject you are so passionate about that you're naturally incited to dedicate a massive amount of work to it. (No trying hard here, only natural drive.)
Have a clear enough approach of the subject, so that your work is very effective. (No working hard here, only naturally exploring threads.)
Happen to be so talented at this subject that this whole process is enough to make you elite. (No trying hard here, only being who you are.)

Most people don't pass step 1.

That shouldn't prevent us from not having success at a smaller scale, but by doing what we love, and not trying hard :)

Antifragile (Nassim Nicholas Taleb, 2012)

2022-06-25T00:00:00Z

I've read Antifragile from Nassim Nicholas Taleb, and it was quite interesting.

The point of the book is that the usual spectrum we consider when pondering fragility, which goes from fragile to robust, is actually only half of a larger spectrum, the missing half going from robust to antifragile. Antifragile systems are systems that explicitly improve when submitted to shocks, errors or mishaps. The book contain various examples: natural selection relies on variability, which itself comes from random mutations in the DNA; the human body builds resilience when it gets sick (e.g. vaccination); etc.

An important characteristic of antifragile systems is that they frequently endure small shocks and errors. Small enough not to bring them down, but sizable enough for them to be valuable to the system. Antifragile systems tend to be organic, complex, and decentralized systems, which grew from a bottom-up build-up, rather than a top-down design.

The book builds on the Black Swan idea developed by the same author in a previous book. This idea stipulates that it is useless to try to make models to predict the future, because at some point some shit we never saw before will hit the fan, having a massive impact on everything we take for granted. Such unforeseen events (e.g. wars and epidemics) are so big, that History as a whole is mostly shaped by them, and is therefore a sequence of twists and turns, like the story of a novel, rather than anything smooth that could have been modeled.

In my opinion, the most fascinating part of the argumentation in the book is the one about non-linearity. Basically, Taleb argues that everything good in life (or in business, or in whatever system) comes from rare opportunities having a massive payoff, not from smooth very-focused sailing. Therefore, all one needs to do is to repeatedly put oneself in situations in which the payoff can be huge, and in which the worst case is bounded (what he calls convex situations). Very focused undertakings with "strategic" plans tend to be the contrary: the nominal course of events is the actual best case, but in the meantime anything can happen that will make it go berserk (concave situations).

That's why the author despises so much everything that is top-down, bureaucrats, bankers, politicians, strategic visions, etc. The best things happen by playing around and tinkering stuff with trial and error. The book gives several examples of the history of science having been rewritten to make it look like some discovery was inevitable, when in fact it was some experimentator playing around in the lab.

I found general idea of antifragility quite interesting, and ever since I've read the book, I've tried to apply this new concept in both my personal life (I guess I should try to be less of a control freak) and my professional life (when thinking about the software systems I develop). The book offers no magic repice on how to make a system antifragile, but rather various heuristics of what such system usually looks like, so I guess one must pass by some trial and error before getting the hang of it (trial and error being one usual characteristics of antifragility).

I am only moderately convinced by the idea of antifragility and related ideas expressed in the book. Since the author is dealing with systems that are immensely complex and that are deeply understood by no one, many of the author's argument are based on heuristics, anecdotes, and intuitions. Which doesn't mean that the ideas are incorrect, but that they're more suggestions and interesting perspectives to look at things, rather than a complete theory of how things works (which makes sense, since the author seems to dislike such theories).

The recurring thematic which I disliked the most in the book is the anthropomorphism around nature: the author truly is a fan of "mother nature", which is the epitome of a wise and all-knowing antifragile system, in comparison to medicine, which is over-medicating people and harming them in the process. This view seems extreme to me. Natural selection comes from random mutations that are selected for survival: there is no guaranty of speed in the way something will be fixed, and there is no guaranty of optimality in how well it'll be fixed. So to me it's extremely vulnerable to Black Swan events as it's way too slow to handle sudden changes in the environment, contrarily to medicine, which at least has a shot, by virtue of being engineered.

That being said, even without full commitment to the theory, the book offers perspectives which are very interesting and that I'll keep in mind. Furthermore, I rather share many of the views expressed by the author, who places the practitioner over the academic; bottom-up tinkering over top-down designing; natural exercising over treadmill running; city-states over centralized empires; grandma advice over bureaucrats policies; non-interventionism when no intervention is necessary; etc. The author exudes a sort of hippy vibe, if not anarchist at times. Anything related to bureaucracy, MBAs, politicians, corporate bullshit, academic bullshit, etc, is held in contempt. Taxi drivers, artisans, and all the authentic people of life, are respected.

Finally the book is regularly amusing because of the frankness and mockery of the author in the way he expresses his contempt of things he doesn't like. For example, policy makers are "lecturing birds how to fly" when they define a process for something that could have been perfectly working without their intervention.

Quotes

It is far easier to figure out if something is fragile than to predict the occurrence of an event that may harm it.

Just as we are not likely to mistake a bear for a stone (but likely to mistake a stone for a bear), it is almost impossible for someone rational, with a clear, uninfected mind, someone who is not drowning in data, to mistake a vital sign, one that matters for his survival, for noise — unless he is overanxious, oversensitive, and neurotic, hence distracted and confused by other messages.

If you put 90% of you funds in boring cash (assuming you are protected from inflation) or something called "numeraire repository of value," and 10% in very risky, maximally risky securities, you cannot possibly lose more than 10%, while you are exposed to massive upside. Someone with 100% in so-called "medium" risk securities has a risk of total ruin from the miscomputation of risks.

Reflecting on the observation that the patent for wheeled luggage was given in 1972:

The simpler and more obvious the discovery, the less equipped we are to figure it out by complicated methods. The key is that the significant can only be revealed through practice. How many of these simple, trivially simple heuristics are currently looking and laughing at us?

Think of the following event: A collection of hieratic persons (from Harvard or some such place) lecture birds on how to fly. Imagine bald males in their sixties, dressed in black robes, officiating in a form of English that is full of jargon, with equations here and there for good measure. The bird flies. Wonderful confirmation! They rush to the department of ornithology to write books, articles, and reports stating that the bird has obeyed them, an impeccable causal inference. The Harvard Department of Ornithology is now indispensable for bird flying. It will get government research funds for its contribution.

My experience of good practitioners is that they can be totally incomprehensible — they do not have to put much energy into turning their insights and internal coherence into elegant styles and narratives.

People with too much smoke and complicated tricks and methods in their brains start missing elementary, very elementary things. Persons in the real world can't afford to miss these things; otherwise they crash the plane. Unlike researchers, they were selected for survival, not complications.

Corporations are in love with the idea of the strategic plan. They need to pay to figure out where they are going. Yet there is no evidence that strategic planning works — we even seem to have evidence against it. A management scholar, William Starbuck, has published a few papers debunking the effectiveness of planning — it makes the corporation option-blind, as it gets locked into a non-opportunistic course of action.

The predictors' reply when we point out their failures has typically been "we need better computation" in order to predict the event better and figure out the probabilities, instead of the vastly more effective "modify you expose" and learn to get out of trouble, something religion and traditional heuristics have been better at enforcing than naive and cosmetic science.

Someone with a linear payoff needs to be right more than 50% of the time. Someone with a convex payoff, much less. The hidden benefit of antifragility is that you can guess worse than random and still and up outperforming. Here lies the power of optionality — your _function of something_ is very convex, so you can be wrong and still do fine — the most uncertainty, the better.

What is top-down is generally unwrinkled (that is, unfractal) and feels dead.

Pharmaceutical companies are under financial pressures to find diseases and satisfy the security analysts. They have been scraping the bottom of the barrel, looking for disease among healthier and healthier people, lobbying for reclassification of conditions, and fine-tuning sales tricks to get doctors to overprescribe. Now, if your blood pressure is in the upper part of the range that used to be called "normal", you are no logr "normotensive" but "pre-hypertensive," even if there are no symptoms in view.

Druin Burch, in Taking the Medicine, writes: "The harmful effects of smoking are roughly equivalent to the combined good ones of every medical intervention developed since the war... Getting rid of smoking provides more benefit than being able to cure people of every possible type of cancer."

Postdictors, who explains things after the fact — because they are in the business of talking — always look smarter than predictors.

Pride and Prejudice (Jane Austen, 1813)

2022-05-09T00:00:00Z

I've read Pride and Prejudice from Jane Austen, and I've read it passionately.

The story is about the Bennet family, a family of 5 daughters, whose main goal as young ladies in their era is supposed to be finding a husband. While some of the youngest of the sisterhood seem to be brainwashed by the system, and only desire going to balls and social events in the prospect of finding a husband, the two eldest, and more especially Elizabeth, have more discernment. Although Elizabeth still complies with the establishment, she looks at it with critical look, and is determined not to marry some random guy she isn't interested in just because of money or status.

At a ball, Elizabeth meets Mr. Darcy, a handsome and rich man who would be a wonderful party on paper, but whose pride and disdain towards "inferior" people arouses nothing but detestation of his person. Also, some gossip about his relationships with some people make him even more ridden with disgrace. In the Bennets' town he's seen as the rich man that everybody hates.

The meat of the novel consists in exploring the nuances of the human psychology and how people are in fact more complicated than the assessment that a superficial inspection might yield, and how complicated it can be to truly discover someone (and oneself).

There are two things I liked very much in this novel.

The first one is the level of emotional details we get access to regarding the character of Elizabeth Bennet. This isn't a novel of adventure and action, but rather a character study. An examination of how the mind reacts to some social interactions and new information. Elizabeth passes by all the nuances of the emotional rainbow, with psychological twists and turns, and each step of the way provoked a great deal of empathy to me. The way she handles her emotional state, wise enough to let the time for things to sink in, yet to understand the need to sort them out and make sense of them, makes her a really strong psychological character. I thought the psychology of this book was fascinating, and that Elizabeth was endearing.

The second thing I liked is the other area in which Elizabeth is a strong character, which is her level of self-respect, her sheer non-compromising approach to finding a suitable partner for life (relatively to the historical era she lives in), and the way she's able to take a stand when she needs to. There is one particular moment near the end of the book, where she's under pressure from some character, but she doesn't even flinch. This was glorious to read. She's the hero of her own life.

Jane Austen's prose is particular. It's a kind of sophisticated prose, where nothing is told simply and plainly, but rather using convoluted constructions. For example, many facts are stated as double negatives, but this is the simplest yet. The worst sentences are so long, with so many pieces in puzzling order, that understanding them is like playing multidimensional chess. I found that to read such sentences, I needed to to go with it "intuitively", just letting my mind go with the flow and get the meaning of it implicitly and quickly. Switching to analysis mode fails by lack of mental memory. I wouldn't say that the novel suffers too much from this style; on the contrary, once I got the hang of it, it was rather amusing to read.

Great book.

AI is automation of mental tasks

2022-01-29T00:00:00Z

AI should be called MA, for Mental Automation. The AI hype seems to be convinced that anything a human accomplishes with his brain is smart, but a lot of mental tasks don't require intelligence. For example, recognizing whether a picture contains a bird or not is a mental task (because it is achieved by our brain, and not our hands or feet), but it doesn't require intelligence; it's just a function our brain is able to do. If you needed to be smart to resolve a Google reCaptcha (which is training Google AI), not many people would be able to sign up on websites. AIs from big corporations are trained by crowd-working jobs in the likes of the ones on MTurk. Those are not jobs requiring particular intelligence (even though they call it Human Intelligence Tasks (HITs)). Those are jobs in which you perform stupid mental tasks all day long.

The industrial revolution automated physical tasks. The AI revolution, assuming it is a revolution, is automating mental tasks. Even though AI is presented as a sort of deeper revolution than just automating stuff, in reality its impact is no different than the one of the industrial revolution: freeing the mind from performing stupid tasks by relegating those tasks to machines.

The boundary between "just a mental task" and "something that requires intelligence" is of course blurry, and most importantly, it is evolving with our own intelligence. Just as doing mental arithmetic have been at some point in history something regarded as an intelligent task, it surely lost a bit of this reputation as soon as calculators made their apparition. Surely there are fields which we currently consider to require intelligence (maybe programming), which might become automated once we figure them out a bit better.

Quotes: To Kill A Mockingbird (Harper Lee, 1960)

2022-01-04T00:00:00Z

You never really understand a person until you consider things from his point of view... Until you climb inside of his skin and walk around in it.

Before I can live with other folks I've got to live with myself. The one thing that doesn't abide by majority rule is a person's conscience.

Never, never, never, on cross-examination ask a witness a question you don't already know the answer to, was a tenet I absorbed with my baby-food.

"Yes sir, a clown," he said. "There ain't one thing in this world I can do about folks except laugh, so I'm gonna join the circus and laugh my head off." "You've got it backwards, Dill," said Jem. "Clowns are sad, it's folks that laugh at them."

As you grow older, you'll see white men cheat black men everyday of your life, but let me tell you something and don't you forget it — whenever a white man does that to a black man, no matter who he is, how rich he is, or how fine a family he comes from, that white man is trash.

If we followed our feelings all the time we'd be like cats chasin' their tails.

"Atticus, he was real nice..." His hands were under my chin, pulling up the cover, tucking it around me. "Most people are, Scout, when you finally see them."

The complexity of contentment

2021-09-04T00:00:00Z

Once upon a time, I didn't care about sound quality. I was buying 10€ earphones at some random tech store, used them until they broke, and then bought a new pair of the same. They provided me with music, which quality was the only quality I knew of. And so I enjoyed life, happily listening to music.

At some point, I started to become a bit more serious about music quality. I started with a pair of entry-level headphones from a reputed brand, and when they broke, switched to even better quality (both in terms of sound and robustness). Once I was used to my new shiny headphones, I remember retrying my old cheap headphones as an experiment. The quality was so insanely bad, I couldn't even understand how I could have been listening to this kind of material for so many years. My new headphones were so much better. And so I enjoyed life, happily listening to music.

The point of this story is that it seems there is no difference in terms of contentment between both eras (cheap headphones, good headphones). In both cases, I enjoyed life, happily listening to music. The only difference is that the contentment of the good-headphones-era relies on something that is more costly, and overall more complex. More complex because having access to decent sound quality gives you access to nuances you didn't notice before (does the sound profile favor bass or highs? etc), and requires everything else (your audio source, sound card, the recording itself, etc) to be up to this quality. So, apparently, the only thing I've done is increasing the complexity of my contentment. This sounds like a bad thing.

Of course, there is something else that has increased. That would be what we could call the sophistication of my contentment. Or maybe the expansion of my mind. Basically, the concept that underlines the fact that I have now access to more details in the music I'm listening to, and more generally to a better experience. Would have I ever really enjoyed Pink Floyd's Comfortably Numb's guitar solo as much as I can enjoy it today if I had stuck to my cheap headphones? Probably not.

So, if we assume that there is inherent value in expanding the sophistication of our contentment in order to live richer experiences, we are facing a trade-off: the more expanded our mind, the more complex our contentment, the harder it is to maintain, and the more painful is the risk of losing it.

An example in which the trade-off is certainly not worth it is drugs. Some drugs allegedly gives you access to an expansion of the mind one cannot even fathom without having tried it. But they lead to a contentment that is so insanely complex (costly, terrible hangovers, dangerous for health, risk of addiction, risk of overdose, etc) that the contentment will eventually disappear when it starts being crushed by the weight of the complexity. (In comparison, good headphones look like a really good deal for mind expansion!)

Curiously enough, I can't find a reverse example where being content of something too simple would be lacking in terms of expansion of the mind. Maybe I'm just not imaginative enough, or maybe it just says something deeper about the trade-off: if being content is inherently more valuable than being sophisticated, then good answers to the trade-off will be skewed towards simplicity.

One application I can find from this insight, is that maybe we should slow down work and produce/consume less stuff, which only purpose is to obscenely complexify our contentment. That would let us have more time to enjoy the simple things.

On the tracks of Mission Impossible: Fallout

2021-08-15T00:00:00Z

Two years ago, I recreated the opening sequence of Midnight in Paris (some 60 sixty shots in various Paris spots). This year I went again on some movie tracking with Mission Impossible: Fallout, which features a big action segment in Paris. Since Tom Cruise (I'll call him Tom) was busy making the new Mission Impossible, I couldn't get him to work with me on a full recreation, so I settled on chosing about 30 shots from the segment, which I went to photograph myself.

As in many other such movies, the scene involves a fair amount of teleportation accross Paris, but it does feature some local consistency; most importantly, it uses actual urban elements to serve the action. They did their homework! In this article, I focus on a few segments of the action scene which are locally consistent in Paris. I present comparisons of my own photographs (left) with shots from the movie (right). You can click on the pictures to see a higher-resolution version.

An overall description of the scene: French forces of order (apparently the police and the RAID) go fetch a terrorist to transport him somewhere. Tom Cruise has been commissioned by some shady organization to steal the terrorist from the police and bring him to them. Tom being Tom, he agrees to the deal, but secretely intends to keep the terrorist for himself and his own virtuous counter-terrorist organization. Meanwhile some other secret agent follows everyone on motorbike and intends to dealt with the terrorist by herself.

1. Ambush, Bercy.

Everything starts when the police goes fetch the terrorist at the French Ministère des Finances, in the district of Bercy. The terrorist is then transported in a truck on the Pont de Bercy.

Once on the Left Bank of the Seine, a setup road accident makes the police take an alternative itinerary, which consists in taking a covered pass at the Quai d'Austerlitz.

In this pass, Tom ambushes the convoy, by bulldozering the truck containing the terrorist into the Seine, with his own truck, and then flees the scene.

Since the terrorist organization notices that Tom is going out of plan, a bunch of their henchmen embark in their cars to try to follow him. This happens at the Viaduc d'Austerlitz, not far away from the ambush.

Some more pics

From left to right: 3 more pics of the Quai d'Austerlitz, and another pic from the Viaduc d'Austerlitz. The pass from the Quai d'Austerlitz is covered with graffiti, which I guess were removed (digitally?) for the movie.

2. Truck pursuit, Rue de Nevers

While Tom's friends are retrieving the terrorist underwater, Tom is being chased by the police in his truck. He teleports to the Pont Neuf, which bridges the Île de la Cité and the Left Bank.

In the continuity of the Pont Neuf is the Rue de Nevers. This is a very narrow street, with a scottish pub (The Highlander) at the begining.

Tom and his buddy eventually crash the truck into the narrowest part of the street, but it was all a plan from the beginning, because their bikes await them here!

They photoshopped the end of the street to make it look like it leads to some other street, even though it's actually a cul-de-sac. It's still technically a Rue ("street") though, because before the end you can turn left and end up in another narrow street (Rue de Nesle); it can hardly be seen in my picture.

3. Bike pursuit (1/2), Saint-Louis

Once on his bike, Tom teleports to the Pont de Saint-Louis, which bridges the Île de la Cité with the Île Saint-Louis. He bikes his way through Saint-Louis before taking the Pont Louis Philippe which bridges the Île Saint-Louis with the Right Bank.

They photoshopped a bit of Eiffel Tower at the top right, just to make sure we knew this was still happening in Paris (and to create chaos in my attempt to identify where it was 😠). In reality there is no Eiffel Tower behind those building, but rather Notre-Dame de Paris. In my picture, you can see the crane that is used to repair Notre-Dame after its fire.

Les Invalides in the background is real this time.

One more pic

Notre-Dame being fixed just behind the building of the first shot.

3. Bike pursuit (2/2), Opera

Tom then teleports to Rue des Pyramides.

The biggest lie Hollywood spreads about Paris is the idea that the city is not under constant work. Everywhere.

Because police is everywhere, he needs to take an underpass at some point in the street; which is a true underpass!

Yeah I didn't even try this one. Don't wanna get ran over by Tom Cruise.

Emerging from the underpass, Tom turns left on the Avenue de l'Opera, passing by the Royal Opera restaurant, and finally biking like hell towards the Opera itself.

The third part of the bike pursuit is completely insane (teleporting to the Arc de Triomphe, taking the roundabout there the wrong way, teleporting to Montparnasse, getting wrecked by the car, escaping in the Paris sewers, teleporting to the canal Saint-Martin), so I didn't even try to cover it.

At this point, Tom meets with his friends who have the terrorist, and they quietly go away in a car.

4. Car interception, Rue du Rocher

While Tom and his friends are quietly driving with the terrorist, Tom's competitor intercepts them at the Rue du Rocher.

The Rue du Rocher is a street with an overpass above another street (Rue de Madrid). This is taken just at the overpass. Those streets are near the Gare Saint-Lazare, at a point where there is a lot of elevation gain, so it makes sense some streets can overpass some others.

Some more pics

5. Car pursuit, Saint-Gervais

Game is on! The competitor is in pursuit of Tom's old BMW. They teleport to the Eglise Saint-Gervais, around which Tom drifts like a boss.

They then turn to the Rue des Barres, which starts with a restaurant.

At the end of Rue des Barres, Tom literally drift down some stairs!

The pursuit then goes on in Rue François Miron.

More pics

From left to right: the Saint-Gervais chuch; Rue de l'Hotel de Ville, which makes the junction between the church and Rue des Barres ; another shot from Rue des Barres.

6. Wrap-up (1/2), Quai Saint-Michel

Once everything is over and Tom has the terrorist, he goes for a bit of chatting with the organization he was dealing with. They chat at the Quai Saint-Michel, where we can see Notre-Dame.

7. Wrap-up (2/2), Jardins du Palais Royal

He also goes smooth the rough edges with his spy competitor, who is kind of his friend anyway. They go chat at the Jardin du Palais Royal, which I hope could be as deserted and quiet as it is in the movie.

One more pic

Another spot at the Jardins du Palais Royal

TL;DR: Deep Thinking (Gary Kasparov, 2017)

2021-06-10T00:00:00Z

Chess engines:
- In average, there are 35 legal moves available when it's someone's turn to play. A skilled human player is able to immediatly spot 3 or 4 moves that are "plausible" and then study them to elect the one they think is the best. The intelligence that allows them to spot those 3 or 4 candidate moves is not well understood, so the machine has no other choice than studying all the available moves. Basically, a machine plays with a branching factor that is tenfold this of a human player. Chess engines do have various pruning methods, although they're not necessarily reflective of human reasoning, nor as effective.
- Both humans and computers need to be able to evaluate a given snapshot of the board to determine what advantage/disadvantage this position holds; this is called the evaluation function. Humans' evaluation function is far more sophisticated than computers'. The reason computers' evaluation function is weaker is because 1. We don't know how to turn all this kind of human intelligence into programming and 2. Even if you add some intelligence, the evaluation function costs more time, so the engine can't go so deep. There is a trade-off to make between the sophistication of the evaluation function and the depth of the exploration. Modern engines go so deep that the evaluation function doesn't need to be that much sophisticated.
- The only chess skill that a machine has is the tactical skill, which is the ability to calculate a sequence of moves in advance ("if I attack his Queen, he'll need to move her, the only available square is here, at which point I'll be able to put my knight here, but this is defended by his bishop, unless I advance my pawn here", etc). In skilled human play, the game is driven by a high level strategic skill, and tactics are used to enable the strategy at each step of the way. The intelligence to strategize is not well understood and haven't been programmed into machines. So computers play without strategy.
- How do computers can win with having a branching factor handicap, an evaluation function handicap, and a strategy handicap? => By adding more processing power. No need to care about the branching factor if you have enough CPUs to handle it, and no need to care about strategy if you extend your tactics to 18 moves ahead.
- The improvement of chess engines had nothing to do with resolving the mysteries of human cognition. It had everything to do with Moore's law (computing power doubles every 2 year) as well as various algorithmic improvements, most notably in pruning.
- In 2017, AlphaZero was the first neural-network-based chess engine to beat the top brute-force-based search engine (Stockfish), after 9 hours of training based on self-play. Its gameplay was described as "alien" by top humans, and shows how far humans are from actually playing top chess.
- Endgame tablebases contain all possible combinations of endgames where only a limited number of pieces remain on the board. The biggest tablebases, the Lomonosov tablebases, compiled by the university of Moscow, know the perfect outcome of any position involving 7 pieces of less.
Kasparov vs. Deep Blue:
- Although the most publicized event (Kasparov's defeat) happened in 1997, it was actually the rematch of a first edition that happened in 1996, in which Kasparov beat Deep Blue.
- In the 1996 event, there was great collaboration between IBM and Kasparov, and the whole match was more of a science project than anything else. When IBM saw the potential in publicity and organized a rematch for 1997, they switched to battle mode, cut communications with Kasparov, hired grandmasters to help them improve Deep Blue, and refused to publish any game from Deep Blue prior to the rematch.
- Because chess engines have no notion of strategy and their search horizon at the opening can't see beyond the middlegame, the way to beat them is to play a very defensive and passive game to force them to attack, at which point weaknesses will appear in their structure, that will be exploitable in the endgame. The problem then is that chess engine are absolute beasts at defending endgames; if there is one single combination that allow them to survive, they will find it; if the opponent make one single mistake, the outcome could be entirely reversed.
- This put Kasparov in inherent difficulty, because Kasparov's natural style was to attack vigorously. Restraining himself from playing is own style was psychologically draining.
- Kasparov won the first game using this strategy, with the white piece. However, he lost the second game, which psychologically destroyed him, for multiple reasons:
  - Because this time Deep Blue actually attacked quite vigurously and solidly, and Kasparov became entangled in his own passive defense, which was absurd as he was the one supposed to have an aggressive style.
  - Because Deep Blue was playing quite differently than the day before, which indicated that custom tuning was taking place between games, and Kasparov started to become suspicious that one move in particular could be coming from a human and not an engine.
  - Because he resigned on move 45, angry at himself for having been directed to a losing position, without analysing the position well enough. There was in fact a perpetual check that could have allowed him to draw the game. His team informed him of that the following morning, which devastated him.
- Games 3, 4 and 5 were drawn.
- In game 6 (the final game), Kasparov volontarily played a dubious move which was risky, but only if Deep Blue was able to realize that it needed to sacrifice a knight to take advantage. Kasparov believed that the engine was not powerful enough to find it. Yet Deep Blue played the knight sacrifice, which allowed him to wreck Kasparov's defense. Kasparov resigned. It was later revealed that the engine was not powerful enough to compute this move, but engineers hard-coded it the very morning of this game as they were analysing this specific variation with grandmasters.
Opinions on technology:
- Kasparov is a proponent of automation, which expands our intellectual horizon by making us able to focus on things on a higher intellectual plane. In the specific domain of chess, chess engines did not made the game uninteresting, but to the contrary more interesting. The generation of grandmasters who grew up with engines are the strongest chess players in history because of the insights they get from the engines.

The first thousand

2021-04-21T00:00:00Z

Last November I watched The Queen's Gambit, and it was excellent enough to motivate me to learn chess. My only experience with chess then dated back to my teenage years when I looked up the rules of how the pieces moved, tried a few games against the computer in the easiest possible mode, lost all of them, at which point I decided that this game was stupid. But Beth Harmon got me motivated, and I wanted to give it a more serious try, and there I discovered my new favorite pandemic hobby.

I've now crossed the rating threshold of 1 000, and here I am doing a bit of journaling. There are plenty of technical resource on the Internet on how to get good at chess, so I won't be giving any such advice here, but will focus on general things I've learned which might be interesting to beginners or even non chess players.

If I was to describe what is a level 1 000 player according to my self-evaluation (of my top form), it would be something like: If the situation is simple I can play the best move. If the situation is complicated I'll most likely play a bad move. Otherwise, I'm able to elect a few candidate moves that are reasonable, but because I don't have any sort of strategic view of the match, I don't really know which one to play.

My rating evolution since when I started playing chess. It's basically a 3-acts story: Act I: I have no idea what I'm doing. Act II: I am a God. Act III: Looks like I'm not gonna be grandmaster next year after all.

Experience matters so much

Initially I had this idea that chess was some sort of scientific game in which you could win if you were clever enough — some sort of advanced IQ test. The reality is far from it. Sure, you need to be able to get focused, think deeply, and make a bit of calculation in your head, but my experience so far is that chess is mostly about pattern recognition. That is, training your brain to recognize patterns indicating that you're in a danger, or that there is an opportunity to gain advantage over your opponent, etc. The game is simply way too complicated to get it right by the sole power of thinking.

This is especially true when you begin. At this point, there is a limit to where concentration can get you, even for simple things like not losing your pieces in stupid ways. You need to blunder, blunder, and blunder again until your brain naturally integrates the game's dynamic, at which point an alarm bell start ringing when one of your pieces is under attack, and it becomes way easier to play correctly.

My most important realization was watching grandmasters commenting live while they're playing on YouTube, and seeing how important instinct is in their decision process. This "instinct" is the result of all their games played, which makes them (consciously or not) recognize patterns they've seen before, and knowing how to react. At a beginner/intermediate level, this is mostly about not hanging your pieces, spotting possible checkmates, identifying opportunities for tactics, and so on.

On my way to 1 000, I've blundered in the most bizarre of ways (what could be called "brain bugs"). At some point around 800 I would be proud to position my queen in front of a rook, thinking that I was pinning the rook to my opponent's king. Not much later I would try to fork my opponent's king and knight with my own knight. My most recent brain bug is forgetting that my pawns can take pieces, so sometimes when my opponent is exchanging a piece I think that I've just lost the piece. I have no solution to those brain farts other than playing until each one of them is consumed and gone for good.

Safety is hard to evaluate

In many real life things, there is an idea of margin of safety. For example, if you walk near the edge of a tall building, then there isn't much margin of safety on the danger of falling. Sure, you're gonna be careful where you walk, but what would happen if a strong wind suddenly arise? Or if a mad person pushes you? Now, if you distance yourself many meters from the edge, you're adding a margin of safety, which protect yourself even against those unlikely events.

In chess, you want safety for your king, and it's of course most comfortable if you can have it with some margin. An example of no margin of safety would be "my opponent can checkmate me on his next move", where you're forced to do something to avoid this terminal fate. But you have in fact already some chess level if you're able to spot that you're in such danger in a first place! For the simple reason that sometimes it looks like you're safe with margin, but it turns out that you were no safe at all! The usual clues that the brain is looking at to evaluate safety can be very misleading in chess. There are 2 specific patterns that I've identified (and surely many more I've not yet):

Thinking that you're safe because of the "visual" reinforcement around the King. The idea is that in real life if you want to protect a king you mostly need to have a lot of bodyguards around him. Bonus points if the enemy is far away. Of course, chess is harder than that.

One of my first encounter with a Queen+Bishop battery (rated 520 at the time). I was playing black and had my King nice and comfy protected by three pawns and a rook. My opponent was moving his Queen for some reason, so I attacked her with Bc6 (my bishop is protected by my own Queen). The reason my opponent advanced his Queen is to align her with his bishop on d3 on the white diagonal (this is called a battery). This allows the white Queen to take the pawn on h7 and check my King. The King cannot take the Queen back because it is protected by the bishop on d3. The King has nowhere to escape which isn't attacked by the Queen. This is checkmate. Mistakes were made, lessons were learned.

Thinking that you're safe because you're much "wealthier" than your opponent. At a beginner level, lots of blunders and mistakes happen, which can result in very polarized games where one side takes complete advantage over the other side, this advantage being materialized by having more pieces ("material") than the opponent. If you're the one having the advantage in such moment, it seems like you're invincible, and that whatever you do, you can't make a mistake that would be big enough to dethrone you from your supremacy. Wrong, wrong, wrong. It's actually very simple: the minimum number of pieces needed to deliver a checkmate is 2 (it depends on the pieces, but Queen+King or even Rook+King are well-known fatal combinations if you can't or don't defend them). So it's not over until it's over.

My worst (but, deserved) defeat (rated 874 at the time): I was playing white and because I was up a Queen I thought I couldn't lose. I was moping up the remaining black pawns with my Queen ("just to be sure") while dodging harassment from my opponent's Rook, until he started activating his King to coordinate with his Rook, which I overlooked because I had tunnel-vision on the idea that he could never get my King with his Rook alone. We eventually reached the position in the picture, which is mate-in-1 against me. The only way to prevent mate was to check his King, but I played Qf5 to attack his Rook instead. This is just one episode in the long series of "So you're telling me I also need to think during the endgame?"

Wishful thinking will lose you

I would say that it's good to have hope in life, that is, to wish that things will go for the best. However, problems will start to appear if you're using what you hope for to actually plan the future. I think this is an application of wishful thinking, although the notion of tunnel vision is also often used in chess commentary.

In chess, when you calculate possible outcomes of a move you're considering, you must make hypothesis about how your opponent will respond. At this moment, you can wish for your opponent to respond in a way that is convenient for you, and it is very tempting to transform that wish into a tactic. Obviously, your opponent is under no obligation to play according to your wishes, and in practice they won't. They will only punish your hope. So what you should do instead is think about how your opponent could reply with the move that would be the least convenient for you, and discard any move that can result in a disadvantage because of such possible response.

At low ratings, wishful thinking can actually be productive, because your opponents don't play accurately, so this allows you to take shortcuts that would otherwise be punished harshly. But as you progress, wishful thinking becomes more and more catastrophic, because your opponents are more and more able to find the best replies to your moves.

So, basically: plan for the worst, and don't take any chances.

There is one specific kind of situation where you can think wishfully: a losing endgame. At this point, your only hope is that your opponent will make a mistake, so you can set traps up and hope for your opponent to fall for them, even if those traps could turn against you with a vengeance (the worst that can happen is that you'll lose faster, which doesn't affect the result). This is one area where chess engines are weaker than humans, because chess engines assume their opponent play perfectly, which disallows risky traps. Not that it makes any difference for them since chess engines rarely end up in a losing endgame. However, you should always take the accuracy evaluation of your moves by an engine with a grain of salt if you were playing a losing endgame.

Elo is Hell

The activity of chess is equipped with a tool which originates directly from hell and whose goal is to rank every single player in the world on one axis from top 1 to bottom 1. This tool is the Elo rating system, whose name comes from Arpad Elo, the inventor of such system. The algorithm behind this system takes 2 rating values involved in a match, and, according to the outcome of the match (victory from one side or draw), affects a new rating to the 2 players. If you win against someone your rating, you win some bit of rating (he loses some bit of rating). If you win against someone higher than you rating, you win big time (he loses big time). And so on.

If you take a look at various online communities (/r/chess, YouTube, etc), you realize how much players are obsessed with their rating, as if it is the definition of their entire chess identity. The anxiety induced by this obsession is well-documented on Reddit and posts about it comes up regularly. YouTube is on it too.

My experience is that this is particularly true with online chess when you play against strangers you know nothing about except a pseudonym. Clearly the most fun games of chess I've played are the ones over an actual board against my sister at Christmas, and the ones I played online against a friend who is rated 1,500, who beat me 3 times in a row, but which was extremely exciting, educative and fun. I actually defended quite well in those matches and we both had an accuracy of above 80%. I think playing against someone I knew made me way more solid than the usual because there was extra-stimulation to show him that I had some level.

Another thing to take into account is that ratings are variable across platforms (Lichess is known to have inflated ratings in comparison to chess.com), and also variable across time controls on the same platform (10-minutes games are way more popular and therefore less demanding than say 60-minutes games).

Finally, because your victories and defeats depend a lot on your level of fatigue, your mood of the day, etc, you need many many games until all factors gets blended together and it levels off to your "true" rating. In this respect I think one of my strengths is my consistency. If you look at the graph at the beginning of the article, there is no roller-coaster business going on, it's just one smooth evolution. There are 2 ingredients to it: regularity (I play one game everyday), and focus (when I play this game I eliminate any distraction and play seriously).

This discipline is not always exciting (although productive and intellectually satisfying), so I have a get-away which I use to have the most fun at chess: blitz games. The 2 ingredients of my blitz games are: irregularity (I play many blitz games in one row then will stop for some days), and distraction (I put on some music, and play fancily, looking at what happens if I sacrifice some pieces or stuff like that). Without much surprise, Elo evolution is more roller-coaster-like on my blitz game.

Blitz games are were I test all my fancy what-ifs for fun ("What if I sacrifice my bishop here?", "What if I launch an attack here?", etc). So far the results indicate that I should not do that, although I think it adds useful data to my biological neural network.

I think it's important for anyone to have a space (like my blitz games) where they can play chess without feeling that there are any stakes at play. Think about it this way: games in which Grandmasters see their rating affected happen on a few occasions in one year. The rest of year, they play hundreds of games (as part of their training, or in unrated tournaments) where their official rating is not affected. Like a Grandmaster, you are also entitled to play chess without being always in the scrutiny of your rating. So, use a side account, or play a different time control, or whatever, then decide, at your will, when you play a game that will impact the rating that you consider to be your "official" one. For me, it's one game per day. It can be more, it can be less. It even can be none, if you only want to have fun.

Covid and young vs old

2021-04-08T00:00:00Z

I think there is a growing idea in traditional and social media according to which, in the management of the COVID-19 crisis, we are making a trade-off which consists in saving old people's lives, at the cost of very strong restrictions on young people's lives. More precisely, the growing sentiment is that maybe we should reverse the trade-off: old people aren't long away from death anyway, and to give them a few more years, we're wasting foundational years of the younger generations. Maybe we should accept Covid as an inevitability for the oldest, and simply re-open for the young.

The problem with this very high-level, schematic view of the trade-off ("save the olds, sacrifice the young" vs "free the young, sacrifice the olds") , is that it ignores one implementation detail in the way this trade-off is going to be made. As the saying goes, the devil lies in the details. I claim that this detail actually what forces the trade-off to the option we're using today, that is, lock down the young. To explain my idea, I will make a comparison to another health crisis that happened in my country (France) in 2003.

In 2003, France was hit by a heatwave of an intensity we had never seen before. France is very ill-equipped to deal with heat. Basically, we don't have air-conditioning "by default" in our houses and buildings. The result is that many old people — particularly vulnerable to dehydration — died during this heatwave. More precisely, 14,802 people died in a few weeks. When you look at the graph of deaths as a function of time in France, for example to pinpoint the obvious statistical anomalies due to Covid in 2020, you can see another anomaly in 2003, a thin but scarily tall spike, which was caused by this heatwave. In modern terms, we could say that this was a Covid-level health disaster, although shorter in time (and therefore in total deaths).

When this crisis happened back in 2003, there was no disruption to society, no disruption in hospitals, no disruption in intensive care units. There only was the disarray of counting old people dying. How did that work out without disruption in comparison to today's very disruptive Covid crisis? It's very simple: terminal dehydration is usually not accompanied by very alarming symptoms. People dying from it eventually fall into unconsciousness before they heart stops. On the other hand, when people get sick of Covid, they have trouble breathing, so they call an ambulance. The ambulance goes to fetch them, and then they need to enter an intensive care unit to assist them with breathing. It is no more, no less, than this single little detail — the specific way the body is affected — which is responsible for the entire disruption to society.

If you really want to go with the other option of the trade-off (sacrificing the old), then you need to be okay with the idea that when someone will call emergency services and ask for help because she can't breath properly, you will answer: "Sorry, but we are at capacity, so you are gonna die." If you are not okay with this, then you need keep the inbound flow of such patients under capacity, and the only reliable way to do that — pending massive vaccination —, are the series of society limitations that we know (whose specific implementations' efficacy can be discussed).

It just happens that the people in first line — doctors — swear by the Hippocratic Oath, which means that for them, unassisting a person in health-related peril is simply not an option. When society limitations were too light in the surprise of the first wave, several countries actually reached capacity for a few days or a few weeks, at which point a triage needed to be made to decide what patient would have a chance to make it or not. This was only a glimpse of what the other option of the trade-off would look like, and it was enough to create a surge in burnouts from nurses and doctors. So, in the context of the Covid crisis, if you want to sacrifice the olds, you're not only fighting the olds, you're also fighting doctors' health and principles, which make the fabric of our entire health system. This is simply not an acceptable option.

A more sophisticated model for introversion and extraversion

2021-03-30T00:00:00Z

A common characterization you can find on the Internet of introversion and extraversion is that introverted people consume their energy when they're around other people (and therefore need alone time to recharge) whereas extraverted people consume their energy when they're alone (and therefore need to hang out with others to rejoice). Here I suggest a more sophisticated theory in which both introverted and extraverted people consume their energy when interacting socially, but the exhaustion only shows in introverted people because of other circumstances.

First, I don't think that introversion-extraversion is a continuum, but rather two independent traits. Introversion is the ability to find value in alone time, whereas extraversion is the ability to find value in social time. Those two abilities can be balanced, which arguably constitutes healthiest type of personalities. Or there can be an imbalance between the two traits, which yields "introverted" or "extraverted" personalities, to some degree according to the value of the imbalance.

So, whenever you try to hang out with introverted people, you're actually competing with their own alone time, and they're calculating whether the value they'll get by hanging out with you will be worth the value they get when they're alone. On the opposite, extraverted people are on the lookout for social interactions, because that is a sure source of value to them. There is a sort of belief that extraverted people have an easier life than introverted people because they have greater social support, networking, etc. But that is only as true as there are opportunities to socialize, which is a resource that you sometimes don't control (I'm looking at you, 2020). In other words, introverted people are better at handling solitude.

Naturally, because of their inclination towards alone or social time, introverted and extraverted people will develop opposite habits of socialization. Socialization is a different beast entirely. Socialization is like a muscle. Like any muscle, the pressure it can handle comfortably depends on how much it has been worked out. Like any muscle, it is healthy to exercise, and all sorts of feel-good substances are released when one exercises it. Like any muscle, it suffers fatigue from exercise that is long enough, or that is harder than it can handle.

Because of their social habits, introverted people tend to have an under-developed socialization muscle, whereas extraverted people tend to have a well-developed socialization muscle. Now, since extraverted people are the one running the social show, most standard social situations in life range on a level that is above what introverted people have been trained to handle. Their muscle is being over-worked and the energy wears off rapidly. In extreme cases (e.g. a shy person being catapulted into a big party), the muscle is being burnt out so violently there is no possible enjoyment and not even productive workout going on. On the other hand, extraverted people are simply putting a healthy dose of exercise on their muscle, which triggers liveliness in them, because that's what happens with healthy exercise.

That is the reason why we say that introverted people are exhausted by social interaction whereas extraverted people are energized by it. This is not a good definition of it. This is merely an observation of the consequence of it in some specific circumstances. The point being, introverted people can also energize with social interactions, only if they can find a social setting that is appropriate for them; and extraverted people can also get exhausted by socializing, if they abuse it and forget to add distance to have a rest.

The Inanity of Work

2020-12-30T00:00:00Z

I work 40h per week, which means that I spend 24% of my living time working. That number absolutely doesn't mirror the amount of my time it feels work is taking. I can start by excluding sleep from the calculation: I spend 36% of my awakened time working. That still doesn't really feel like it. To be fair the one hour of breakfast and shower before work isn't valuable free time because my mind is already focused on the fact that this is going to be a workday, and because I can't take my time. Same deal for lunch. And while I'm at it, same deal for the entire freaking evening, because then I'm tired from the day of work, I'm on a tight schedule before I need to go to bed, and, if I'm unlucky, I'm working on a stressful project that's actually still occupying my mind. So the only true statistic is that I'm working 5 days out of 7, and so, work is taking 71% of my time.

Why is it that I'm spending that much time at work in 2020? I can understand that in the era of cavemen, there wasn't any infrastructure to stabilize people's quality of life and everyone had to be constantly on the lookout and hurry for food, and that they were working towards this goal most of the week. But why is it that in 2020, with all the civilization, and all the modernity, I'm still spending 5 days out 7 working my ass off for the day and that our entire citizen lives are still basically organized around the concept of work. Shouldn't we be resting up a bit at this point?

Why do I work? I work to produce some value, so that someone else who enjoys this value can consume it. Part of the money this person spends to consume this value comes back to me in the form of my salary, so that I can myself consume stuff I enjoy that some other people worked to produce. That being established, it becomes clear that we actually control the amount of work that needs to be done with the amount of stuff that we decide to consume. And that is the problem: people definitely like to buy all sorts of stuff, as it is being clearly established that the holy grail is 🌟 purchasing power 🌟. However, many people also dislike work. They don't like mondays, they like fridays, they complain about their bosses, and so on.

For many people, it's worse than that, because they have more responsabilities than just work, like a house and children. At this point, there is so little free time remaining that you've learnt to make the most efficient usage of every minute of the day, and you've become a machine whose time is partitioned into work, other responsabilities, and enjoying your consumptions.

I'm not sure we're fully realizing the compromise that we're making. We could just decide to grab some books to read and some coffee to drink and chat with the people we like and take some walks in the woods and make drawings and shit, and we definitely wouldn't have to work that much. But oh no we want cars, we want pools, we want playstations, we want holiday trips, we want big bang weddings, we want to go to Mars, we want to order miriads of wondeful things from the Internet. And that brings up so much fulfillment in our lives that we're perfectly willing to work 5 days out of 7 to produce all that stuff, even though it mecanically shortens the window of time that remains to actually enjoy aforesaid stuff.

It's not all back or all white. We could just decide to slow down, work less, and take more time to appreciate things. One of the life lessons I've come to learn those last months is that taking my time and enjoying the immediate present is an incredible medicine against stress. First, it forces you to recognize and fix the elements of discomfort that you would ignore if, instead of being focused on the now, you would just be gliding over it. Second, it abstracts time away, as there is only one place in time you're existing in: now. Third, it doesn't require any spectacular activity, because even the most mundane things become enjoyable and noble when you do them with focused application.

When we're not in the moment, we tend to either focus on the past or on the future. We look at everything that we have accomplished, and plan on accomplishing more. The problem is that if we never stop in the middle to take the time to watch around and enjoy, then it all becomes useless. We're just hamsters running infinitely on a wheel, contemplating how many revolutions we've made so far, and planning on running even faster. I would argue that the consumer society doesn't really goes into the direction of "taking the time to watch around and enjoy", as the key for success is considered to be 🌟 growth 🌟. Just as you think you can take your time and rest, you need to get back to work.

And work, there is. There is so much work to do, because everything is so complicated. Whenever you scale up a project, layers of abstraction start to appear that need to be maintained and the maintenance itself needs to be maintained and work is popping up exponentially like wild fire, to the point where it becomes hard to identify how one single piece of work in the whole system is accomplishing anything for the end goal. Look at any software company that has a popular product, for which it seems to require years for one feature to be added, and yet they have hundreds of engineers. What are they all doing? Well, I can answer that. They're reading the documentation of their testing tool to try to debug a test, or they're fixing their local or staging environment, or they're preparing a migration to move one piece of data from point A to point B, which will make their situation slighty better after, and so on.

This is why side projects are so fun and liberating. They're free of all the bullshit that needs to be done to make something production-ready, and give the illusion that you can accomplish so much with so little. Your productivity on a side project seems to be orders of magnitude bigger than your productivity in an enterprise environnement. I guess there is some sort of Pareto principle of work which would be like: 80% of a project (its "meat") will require 20% of the work. The other 80% of work cover all the details and technicalities to actually make it production-ready. This why you can make a demo in 2 days for a project that will take 2 months, or make a side project in a week-end, that would require a big corporation 2 years to ship.

There is a certain glorification of work, especially in enterpreneurs at the transformative stages of their projects. This idea that the key to success is to work long hours and week-ends so that you can produce much wealth and change the world. In fact you're just dealing with the labyrinth of inane complexities that arise whenever you're making a project, and there are so many of those complexities it feels like they should all be quickly taken care of in order to accomplish something that actually looks meaningful. Most likely, it's being done in such a hurry because of an artificial deadline, or just to keep up with the competition, because you don't want to be the one that bails out on velocity.

There are obstacles on the road towards less work. The first obstacle is capital and its expected returns. Rents and mortgages need to be paid, and so, money needs to be obtained. It doesn't matter whether the wealth you're producing to win this money is actually relevant or not, the only thing that matters is that this money is going to the capital's owner (your landlord or your bank). The solution to this obstacle is to own capital oneself, that is, buy a home and finish paying the mortgage. Hopefully, you do it before retirement, since at this point you effectively don't work anymore.

The second obstacle is the structure of the world of work, where it's not always easy to find meaningful part-time work. Even if you as an individual would like to slow down because you're anti-consumerist and anti-work, the rest of society isn't, and so you would be swimming against the flow. It's hard to justify working less for no reason without being considered lazy, it's hard to socialize if you don't work in a society in which everyone else is working, and it's simply hard to find a good job opening that operates out of the standard 5-days week.

Work is so foundational to the way our lives are organized that it's hard to imagine a life without work, or simply with less work. Starting from there, only some marginal foolish people like me lose their time writing articles about the absurdity of work, as the others are either occupied with something else, or don't understand at all, because they like work. So, to end this article, here is a list of the 5 types of workers in this world, and why only one of those types doesn't like work :

Survivors. Survivors have a salary that barely match their lifestyle. That is notably the case of many parents with a low-to-medium salary who have a mortgage on a home, children, and one or two cars. Survivors need to pay the bills and feed their children and they don't have much time to get their spirits entangled in philosophical crap about work.
Time bookers. Time bookers are afraid of free time. Any empty slot on their schedule is a slice of their lifetime that is wasted and could have been spent on some activity instead. Time bookers like (or at least don't mind) work because work is chunks of 8 hours a day 5 days a week of pre-allocated time they don't have to be anxious about filling with something.
Achievers. Achievers like the idea of climbing the ladder. They enjoy the concept of work itself, and make it a part of their identity. What they're building above all is their own career.
Vocationists. Vocationinsts have a calling to do something, and they get paid for it (not always as much as they would like). They often do jobs which result in direct improvements of people's lives (doctors, teachers, trade jobs, etc) or they found a way to monetize their passion or ideas (artists, entrepreneurs, etc).
Lazy valuable bastards. Lazy valuable bastards are the remaining bunch. They're not survivors because their skills allow them to be well-off financially. They're not time bookers because what makes them happy is an ocean of unscheduled free time. They're not achievers because they're not interested in the career video game. They're not vocationists because they don't have a calling (or they find the monetization of it too lame or industrial). lazy valuable bastards are waiting for their lifetime to be wasted on work before they can be reincarnated into domestic cats, and in the meantime they try to have as much rest as possible in the little free time they have.

How Covid Spreads

2020-10-12T00:00:00Z

Very informative article from The Atlantic. TL;DR:

The spread of the virus obeys the Pareto principle: something like 80% of the contaminations comes from 20% of the infected. In other words, if in average one infected person contaminates x other people, that x is the average between many 0s and a few big numbers. In other words, the virus spreads in clusters.
Such dispersion seems to be the result of properties of events rather than properties of the infected people themselves (we talk about super-spreaders when we should talk about super-spreading events). Events to avoid are described by the 3 C's: Crowds in Closed spaces in Close contact.
Backward tracing is preferable to forward tracing. Forward tracing won't yield interesting findings in most cases because an infected person is unlikely to contaminate someone else. Backward tracing is crucial to identify clusters because an infected person likely belongs to a cluster.
Unreliable tests are valuable, as long as they yield no false positives (false negatives are okay). If there is a suspicion of cluster, then everyone needs to be tested cheaply and rapidly. If there is anyone who got the virus, then odds are that many other people got it too. So the test only needs to find a single one of them to raise the alert (some false negatives are okay). However, the test should not yield false positives (or it will raise alerts everytime).
Japan understood all of this in February 2020 and contained the virus without any lockdown despite having some of the densest cities in the world.
Many of the regions most critically hit by the virus around the world might simply be bad luck of having had a big cluster in this specific region.

What if the future is all that is more practical

2020-09-17T00:00:00Z

A common technique to try to predict the future is to think about technology. We take new technology, such as AI, self-driving cars, neurotechnology, etc, and try to understand how society will be shaped once (if ever) they become industrialized. If we feel even more bold than that, we take a mere idea of a technology (rocket-based transportation on Earth, etc) and try to understand how humans will live once it appears for real.

I believe this approach is rather unproductive -- well, as if such exercise of predicting the future can be productive anyway. The first reason is that it's simply too hard to predict the future of technology. According to Neil DeGrasse Tyson, if you look at the archives of technology prediction in newspaper for the last century, predictions obviously become less and less accurate the further in the future they try to predict, and 50 years seems to be the threshold after which they are completely mistaken. So the horizon for our predictions of future technology is 50 years, give or take.

The second reason it's probably a bad idea to use technology to try to predict the future of society is because it's not the way innovation works. At the 1997 Worldwide Developer Conference, Steve Jobs was asked why Apple was dropping development of OpenDoc even though OpenDoc was awesome technology. His answer was that innovation doesn't work by trying to find an application for a technology, but by trying to find the technology to solve a problem. You don't start with the technology, you start with a need.

One of the things I always found is that you've gotta start with the customer experience, and work backwards to the technology. You can't start with a technology and try to figure out where you're gonna try to sell it.

-- Steve Jobs, 1997

When we try to predict the future using technology as a compass, we're doing exactly the contrary Steve Jobs tells us to do here: we've got all those funny new things like AI and self-driving cars, but we're not even sure what the hell they're good for, and we try so hard to make them fit into a model of the future so that we can make prediction about the future, but we're not even sure the future cares about that at all.

Of course, sometimes technology is so crazy predictions are rightfully made about an entire class of usage for it. An example would be Nikola Tesla, who, when he was working on wireless communication, basically predicted cell phones and video-conferencing in 1926, shattering the 50 years limit to an (almost) entire century. Working from home because of Covid and making heavy usage of video-conferencing, I regularly think about this quote and it simply blows my mind that someone already had that in mind 94 years ago.

When wireless is perfectly applied the whole earth will be converted into a huge brain, which in fact it is, all things being particles of a real and rhythmic whole.

We shall be able to communicate with one another instantly, irrespective of distance. Not only this but through television and telephony we shall see and hear one another as perfectly as though we were face to face, despite intervening distances of thousands of miles; and the instruments through which we shall be able to do this will be amazingly simple compared with our present telephone.

A man will be able to carry one in his vest pocket.

-- Nikola Tesla, 1926

Of course, those kind of examples are highly vulnerable to Survivorship bias. Of course we remember the predictions that were correct and forget the ones that weren't. Who knows what else Nikola Tesla predicted that wasn't as accurate as that. Assuming enough people make predictions varied enough, of course some of them will have it right. Doesn't change the fact that there existed someone 94 years ago who was convinced about a prediction he made, and he just happened to be correct. Many people playing the lottery doesn't make the winner any less remarkable. In this case, winning is not random, there is an honest reasoning.

I think the reason we're making future predictions based on technology is because it's the only direction we know how to go in: it's always possible to imagine usages for a given technology, however it's often a billion-dollar problem to imagine a technology for a given idea. So, by lack of genius, we take the easy way, even thought it's doomed to be unproductive most of the time. The evolution of society is a continuous feedback loop between what is possible (technology) and what is imagined (ideas), and successful people are the ones who immediately spot when the technology becomes available for an incredible idea they have. Those who hop on any new tech are just salesmen.

Our obsession of using technology as the only available marker also inhibits us from making predictions too wild, which is a mistake. If I tell you we're going to be able to teleport in the future, you're gonna object by asking me to explain how that is going to be implemented, because you're focusing on technology again. But that is ridiculous, much of what we know about technology will be obsolete in 30 years, why would a technological explanation be relevant to this discussion. This is the third law of Arthur C. Clarke laws:

Any sufficiently advanced technology is indistinguishable from magic.

-- Arthur C. Clarke

This law is cute, but it isn't really helpful, at least not helpful to predict the future. In fact, it pretty much states that if we're using what makes sense today to predict the future, we're gonna at least miss some innovations, because some of those are simply magic from today's standard. But it doesn't tell us which innovations we're missing.

So, how do we make predictions? Well, the wise move is probably to simply stop making predictions. But I'm not very wise. I want to try. My guess, which is rather arbitrary, but which has the quality of being very optimistic, would be this law:

Anything that is more practical will eventually be implemented.

This law predicts the entire future (you just have to dress a list of things that would be practical, and you decide how exhaustive you try to be), but it gives no guaranty as to when the implementation will happen. Most importantly -- and that is consistent with all I've written above -- this laws makes no assumption about what technology will be used for the implementation.

As I'm writing this article before noon, I'm remembering my fridge is almost empty and I'm gonna need to go buy some groceries, or to order a delivery. I think it would be way more practical to just open my fridge and find a perfectly good dish there. My guess is that this one will happen sooner than teleportation.

When do the digits of the Epoch time change?

2020-09-12T00:00:00Z

Approximately, using whole numbers of units commonly used for each time scale.

1599938520
||||||||||- every second
|||||||||- every 10 seconds
||||||||- every 2 minutes
|||||||- every 17 minutes
||||||- every 3 hours
|||||- every day
||||- every 12 days
|||- every 4 months
||- every 3 years 
|-every 32 years

The sane hardship it is to understand that 0.999... = 1

2020-07-25T00:00:00Z

One of the most important realizations that I have had about mathematics is the fact that there is no global definition of what "infinity" is. You can't just drop the word "infinite" in any context, as if one day mathematicians had a meeting to decide the meaning of "infinity" and made it an element of reasoning you can use with any mathematical thing.

In set theory, a set is "infinite" if, for every natural number, the set has a subset whose cardinality is that of this natural number. In functional analysis, a function has a limit L as x approaches "infinity" if, for any tiny ɛ, there is a point after which the function won't ever be farther from L than the distance ɛ. The term of "infinity" obviously comes from an intuition about the philosophical notion of infinity, but it is then defined formally using very traditional and non-mystical notions and notations, and there isn't any global notion of "infinity". You can't take some random mathematical thing and ask "What happens when this goes to infinity?".

Now, when someone comes and says "hey, do you know that 0.999 with an infinite amount of 9s after the decimal point is equal to 1?", what most people do is that they try to picture the number 0.999 with an actual infinite number of nines after the decimal point and then they try to actually reason about this monstrosity. This is an interesting intellectual exercise, but when you're doing that, you're doing philosophy, not mathematics. If you want to do mathematics, what you should be asking back is "What is the definition of a number with a decimal repeating infinitely?"

There are multiple definitions for it, but the one that makes the most sense to me is an infinite series. We can simply state that 0.999... can be written as 0.9 + 0.09 + 0.009 + 0.0009 + ... Formally, it would be written as follows:

This form is very helpful, because the notion of infinite series is very well defined. It is simply the limit of the sequence of the partial sums. In other words, 0.999... is the limit of the sequence 0.9, 0.99, 0.999, 0.9999, etc. Let's call this sequence 0.(9)n for later reference. I like this definition because it reminds me of very important aspects of sequences and their limits that I learned when I was in school:

There is no such thing as an "infinite term" of a sequence (and some teachers won't like it if you ever dare say something like that).
The limit of a sequence may very well be distinct than any of its terms.

I think those two aspects are at the origin of the difficulty that there is to accept that 0.999... = 1. I think that the decimal representation with its "infinite digits" is misleading because it leads us to ponder the notion of an "infinite term" (of finite truncations) all while it is explicitly discouraged as soon as we actually consider the sequence of truncations itself. Then our minds are lost wandering in the vast pastures of infinity where it's hard to understand how a limit may not belong to the sequence itself. I think that what people really mean when they think that it's problematic that 0.999... = 1 is that the sequence of 0.(9)n never reaches 1 no matter how many time you look at the next term.

In other words, consider the set of all elements of the sequence: {0.9, 0.99, 0.999, 0.9999, ...}. This set is obviously infinite, and 1, the limit of the sequence, does not belong to this set. When we ponder the notion of "infinity" in the context of 0.9..., what we might envision is the journey through this "infinite" set. With this in mind, it's hard to see how 1 can have anything to do with this, since it is outside the set.

But this begs the question: what is a "limit"? In layman terms, the limit of a sequence is a real number the sequence is ever getting closer to (without the requirement that it actually reaches it at any point). More formally, it means that for any tiny real number ɛ, there is a rank after which the sequence won't ever be farther from the limit than the distance ɛ. (This is the same definition than the one used in functional analysis I presented in the introduction.) Even without a formal proof, it seems pretty obvious than the sequence 0.9, 0.99, 0.999,... has 1 for limit. And therefore, if you actually understand the proper meaning of the notation, that 0.999... = 1.

Now, since the limit of an increasing sequence also happens to be its supremum (least upper bound), this leads us to another definition, which is the one that is actually used by Wikipedia:

The real number represented by an infinite decimal is the least upper bound of its finite truncations.

What this means is that if you take the sequence 0.(9)n, then the number that is written "0.999..." or said to have "an infinite amount of 9s after the decimal point" is the smallest number that is greater than all terms of the sequence. For example, 3 is greater than all the terms of the sequence, so that's a candidate. Is it the smallest such number? Well, certainly not. 2 is greater than all terms of the sequence and it is lesser than 3. Can we find smaller? Sure. 1 is greater than all terms of the sequence. Is there something even smaller? Hmm... doesn't seem so. I think 1 is the smallest. This, of course, is only intuition so far, but the proof is easy enough to follow.

We're in for 2 months

2020-04-04T00:00:00Z

One of my activities during the lockdown here in France is trying to predict how much time will the lockdown last. The data I'm using comes from here.

Below is a plot of the rate of growth of Covid-19 in Hubei, Italy, and France, starting from the day each region has started its lockdown. The rate of growth at a given day is the number of new cases on this day, as a percentage of the number of cases from the previous day. The rate of growth is constant for an exponential evolution, and is 0 when there is no more growth. (Mathematically, it is the derivative of the function divided by the function itself.)

Source script

Hubei has some statistical aberrations which make the plot goes wild at some places. They may be the result of changes from one counting method to another. For example, at some point they started adding people clinically diagnosed with symptoms of pneumonia (most likely Covid-19) on top of those who tested positive to SARS-Cov-2.

What we see in the plot is that:

Locking down works. For each of the countries, locking down eventually brings the growth significantly down. Italy has been on a smooth decline since the beginning of their lockdown. You may read articles in the press about how they're finally beating the virus, which is just a way of saying that the rate of growth has decreased under some arbitrary threshold. It has been decreasing from the start.
It takes time to kill growth. Hubei needed 30 days for the growth to almost come to a stop.
Even if they don't start at the same rate of growth, it looks that each country is ultimately going to take around 30 or 40 days to kill growth.

Why does it take so much time? I have 2 explanations for it.

Explanation number 1 is the incubation period of Covid-19, which ranges between 5 days and 14 days. This means that the last people who have been contaminated just before the lockdown (which is much of the contaminated people, because of exponential growth) will start going through the disease between 5 days and 14 days in the lockdown. Once they are sick, the symptoms tend to peak between 2 and 3 days in the illness, which is the moment they reach for medical assistance and get tested. So it is expected that the measured number of contaminated people could continue growing up to 17 days after the start of the lockdown.

17 days are still lesser than the 30 days we're observing here, which brings me to the second explanation: the lockdown is not perfect. Some people cannot work from home and still go to work. People need to buy groceries, and go to the shop. People order deliveries, with packing touched by other people. People get sick for various reasons, so they do to the doctor, where other people are waiting. And so on and so forth.

The fact that there are contaminations even during the lockdown seems to be corroborated by another metric, which is: once there is no more growth, how many of all the people who have tested positive are still sick? The answer is: most of them. The following graph shows the number of unrecovered cases of Covid-19 against the total number of cases in Hubei after 30 days of lockdown. That is, once there is almost no more growth.

Source script

We see that even when the virus has stopped spreading, a large majority of all Covid-19 cases are still positive, and it takes another 30 days before most of them recover and there is only a small minority which is still positive.

My initial reaction was that it is no problem to stop the lockdown after the first month, you just have to keep the still-ill locked down until they recover. The problem is that it is well-known that the number of measured cases is way lesser than the number of total cases, because only the worst cases get tested. So we must imagine that this graph only represent a subset of the entire set of Covid-19 cases, and their sizes evolve proportionally. So if you let out people at Day 30, you're actually letting out people among a sh#tload of people who are positive, and therefore at risk of spreading the virus again.

You can read the complete Hubei lockdown timeline here, from which I extract 3 bullet points:

23 January: lockdown
6 March: first day with 0 new case
27 March: lockdown lifted

The rest of the world waited for the last moment to put lockdowns in place, and started experiencing hindsight bias about the fact that it was pretty much announced by China one month before. If this time we stop playing the game of "in our country it's going to be different than in China", then the prediction for the duration of the lockdown is: 2 months.

Thoughts on agnosticism

2019-12-23T00:00:00Z

Can we prove or disprove the existence of god?

It depends on the exact definition of god, but in many of the traditional religious definitions, god hides himself from proof in order to truly test the faith of believers. In this case, his existence is, by definition, not provable.

A relevant question would then be: can something whose existence we cannot prove ("we" as humans) have any impact on the world? I would think definitely yes. Our study of the universe is done either in laboratory, either by observations of deep space through tiny pinholes thanks to our telescopes. The entire field of natural science if therefore based on the assumption of regularity in Nature, such that what we discover on observations of limited scope applies everywhere. It is a very reasonable assumption, because it provides us with a framework to study efficiently, and it gives excellent results that can then be converted into actual engineering that works, at least in the scope we're playing with.

However, it is vulnerable to irregularities that would hide themselves from us, such as god is traditionally defined. For example, god could chose to fulfill some prayers, but stop altering the normal flow of things as soon as he spots you're doing statistics to measure whether prayers work or not. An entity capable of observing all the information of the Universe at once (wouldn't that be... a god?) would definitely detect those irregularities, but we humans are far less powerful than that, and we could clearly get tricked.

In this case, you might think, well, why not believe in god even if I can't prove it; I have little to lose, big to win. This is a famous philosophical argument made popular by Pascal, named the Pascal's wager. But then, you're making an assumption, which is the assumption traditionally made in religion: god is good.

Let me tell the story of an alternative god. This god has created humans as rational animals, who should use logic and the scientific method to improve their understanding of the world. This god carefully hides himself from his creation, such that through this scientific method of them, they can't uncover him. But to truly test their faithfulness to rationality, he put the seed of mysticism and of superstition into the human brain, and because he's sort of a meta guy, he specifically put the seed of belief of himself. He wants humans to be rational, so he wants them to resist the temptation of belief. So, in this world, humans naturally develop an intuition for the existence of god, but they're designed to reject it, because god made it impossible to prove this intuition, and god wants them to be focused on proof. Those who accept the superstition, the believers, are considered deficient, and are sent to hell.

The reason I made up this alternative god, is to show that whenever you think that you have nothing to lose in believing in god, it is incorrect: you actually risk going to hell if it ever happens that my alternative god is real. You might be skectic of my alternative god, because since I just made it up, it surely isn't an hypothesis as solid as any of the religious gods, who appeared in holy books thousands of years ago. But this is just a popularity argument, and since you have zero element in favor of any hypothesis anyway, you can't really argue that any god is more or less likely than any other.

Maybe you think that the most rational move is therefore neither to believe that god exists, nor to believe that he doesn't. But even then, I could tell you the story of a god who only sends agnostics to hell (because they're not brave enough to take a risk, or whatever). Basically, whatever you do, there is possible god that would send you to hell for it. This is what happens with non-scientific assertions (assertions, which, by the way they are formulated, you cannot prove or disprove): there is no optimal move. Such assertions are irrelevant; not because ignoring them is safe, but because there is no insight on what is the safest position.

Notes on nuclear energy

2019-12-14T00:00:00Z

If you want to release energy, then you need to give some force the opportunity to work.

For example, consider a child who is tensing a slingshot. In this state, all forces cancel each other. The force of the child's arm counters the force of the slingshot's elastic. There is no energy released out of this system. But as soon as the child releases the elastic, then the tension force of the elastic starts providing some work. And if there is a force that is working, then it releases energy. In this instance, it releases kinetic energy, given to the rock that is being projected.

There is a force out there which is rather strong: the nuclear force. It is the force which glues together the nucleus of an atom. The nucleus of an atom is made of two types of particles: protons and neutrons (we call them nucleons when we don't need to make the difference), and they're all kept tight together by the nuclear force. Now, if you take an atom, you can't get any energy per se out of its nucleus, because it is stable. And you can't get energy out of anything stable. You need some force to work.

So how you get the nuclear force to work? Well, scientists have made a relevant observation: not all nucleus are as tightly glued as each other (they use the notion of "binding energy" to measure how glued nucleons are together, which is the energy you would be required to provide in order to unglue the nucleons). Below is a graph of how tightly glued nucleus are depending on how many nucleons they contain (the proper word is not "glued", but rather "stable"). As you can see, atoms with few nucleons, such as Hydrogen, are not that much stable; the maximum of stability is reached with Iron; and then stability decreases steadily down to Uranium.

Binding energy of nuclides depending of their number of nucleons. This energy is, by definition, the amount of energy required to separate the nucleons of the nucleus.

So scientists had the following idea: what if we took two low-stability atoms, such as two atoms of Hydrogen, and glued them together to make one atom of Helium, which would be a bit more stable, according to the graph. What would be the point of that? Well, you have to remember that stability comes from the nuclear force. So if you've somehow reached a higher level of stability, then it means you have provided the opportunity for the nuclear force to work. And what happens when a force works? It releases energy. This is nuclear fusion.

With nuclear fission, the opposite is achieved: we take the biggest nucleus, Uranium, which is not very stable, and we split it into two smaller nucleus (fissile Uranium has 235 nucleons, and will fission into two nucleus of around 100 and 135 nucleons respectively). Each of those two children nucleus have a higher stability, according to the graph, so it means that the nuclear force has had the opportunity to work, and in the process, must have released energy.

In both nuclear fusion and fission, the gain in energy eventually presents itself in the form of kinetic energy in the particles at play. Such kinetic energy will make those particles impact the bulk material surrounding them. This will lead to the material heating, and, in the case of civil nuclear, this heat is used to boil water and, ultimately, run a turbine.

But why does the gain in energy presents itself at kinetic energy, and what particles hold this kinetic energy, and from what force?

Fusion

In the case of Hydrogen fusion, a Hydrogen nucleus with 2 nucleons (deuterium) fusions with an Hydrogen nucleus with 3 nucleons (tritium), to very temporarily become an Helium nucleus with 5 nucleons. The resulting Helium-5 nucleus is in such a configuration that a neutron gets ejected out of it at high speed. The rest of the nucleus is ejected at high speed too because of the recoil. The resulting kinetic energy is far greater than the energy required to perform the fusion in a first place. The emission of a neutron happens almost instantly (Helium-5 has a half-life of 10^-22 seconds), so the fusion is usually said to produce one neutron and one Helium-4 nucleus, without even mentioning the Helium-5 step.

Ultimately, the energy of fusion turns up as the kinetic energy due to neutron decay of the unstable Helium 5 nucleus.

Now, I don't have a clear understanding of the mechanism at play which ejects this neutron, but the force at play is, again, the nuclear force. What I haven't said yet about the nuclear force is that if the nucleons get really too close, it starts becoming repulsive. The following digram shows the value of the nuclear force between 2 nucleons depending on their distance. Caution: the value on the y-axis is positive when the force is repulsive, and negative otherwise.

Nuclear force gets repulsive at very short range.

So my limited understanding is this neutron emission is that, after the fusion, the Helium-5 nucleus is in such a configuration, that a neutron becomes too close to its counterparts, crossing the limit where the nuclear force start becoming repulsing, and so gets ejected.

Fission

In the case of fission, a neutron is shot at an Uranium nucleus. The nucleus grabs the neutron, which puts the nucleus into such a configuration that the nuclear force starts shaping the nucleus into two different clusters of nucleons. This reaches a point where the two clusters are separated by a distance big enough for the electromagnetic repulsion of their protons to be greater than the nuclear force, at which point the nucleus fissions into two children nucleus repulsing each other at high speed.

A nucleus having taken a neutron becomes in such a configuration that nucleus start organizing into 2 clusters. In reality, the two clusters don't usually have the same size.

The final force at the origin of the kinetic energy is therefore the repulsive electromagnetic force.

Simple streaming of videos over the LAN

2019-10-24T00:00:00Z

My external hard drive is connected to my Raspberry Pi, which itself is connected to my TV via HDMI. I have a bunch of videos on my drive which I usually watch on the TV using omxplayer, but sometimes I want to be able to watch them on my laptop. I wanted a simple solution without having to make my Pi a full-fledged NAS.

My first attempt was to launch the built-in simple HTTP server of Python into my videos' directory:

python3 -m http.server

And then visit my Pi's local IP in my laptop's browser to get the file listing and let the browser open and read the videos. It works, but it's impossible to seek at arbitrary times inside the videos. Indeed, the server doesn't support the Range header that the browser sends when seeking at a specific part of a video.

I found out that the Python Twisted project comes with a basic web server that is more powerful than http.server and does support Ranges. In the end, the solution to my problem was as simple as:

sudo apt-get install python-twisted-web

and then

twistd -no web --path=.

It takes a little more time to start than http.server but it can seek videos :)

Proof that 1 + 1 = 2

2019-09-09T00:00:00Z

The fact that 1 + 1 = 2 is not an axiom of the Peano arithmetic, but it is fairly easy to demonstrate. The Peano axioms for natural integers are all based on the notion of "successor". The only named integer is zero (0), and then there are five axioms revolving around zero and successors of natural integers.

The Peano arithmetic introduces further axioms for various operations on integers. It defines two axioms for the addition. For any natural integers a and b, and S the notation for the successor of a given integer:

(1) a + 0 = a
(2) a + S(b) = S(a + b)

Let 1 = S(0) and 2 = S(1). Then:

1 + 1
= 1 + S(0)  (definition of 1)
= S(1 + 0)  (axiom 2)
= S(1)      (axiom 1)
= 2         (definition of 2)

The intuition behind the mechanics of axiom 2 is that adding c to a means taking c times the successor of a (that is, S(S(S(S(...(a))))) with c S marks). In more informal terms, a + S(b) = S(a + b) should be thought as a + c = S(a + (c-1)). The right operand is "decreased" by prefixing the whole thing with the successor operator. Eventually it will reach zero and the number of time we needed to decrease it to reach zero is kept track by the number of time we marked the S notation.

Recreating the Midnight in Paris opening sequence

2019-08-04T00:00:00Z

Below is my recreation of the opening sequence of Woody Allen's movie Midnight in Paris. You can find the original one here. I have also a Flickr album with the 60 pictures, as well as a bonus album with extra pictures taken during the project.

I have substituted some shots for other ones, mostly because their spot wasn't available at the time I was taking the picture. I also did not try to imitate the exact framing of the shots in the movie, because I decided it wasn't the optimal choice given the conditions that had changed between when the movie was shot and when I was taking the shots.

Below I break down this project in its three phases: location identification, photography, and editing.

Locations identification

The sequence in question contains 60 shots taken at various places in Paris. The first step was to identify the location of each of the 60 spots where the shot had been filmed in order to go there and take the video. I did not find any authoritative reference on the web that lists those places. The most advanced material I found was this article of The Cine-Tourist which analyses the opening sequence and gives away many of its locations if you're willing to go through the prose. The most interesting take-away from this article is that the locations of the opening sequence aren't random, in fact they match the locations of the events that takes place in the rest of the movie.

Example of location identification with shot No. 48. "Saule pleureur" means "weeping willow". The website from the image in the middle is http://parismamanetmoi.com/2013/02/03/saules-pleureurs-parisiens/

In order to identify the precise location of the shots, I first identified the general area (that is, the street, or park, or place) on Google Maps, and then tried to recreate the exact angle in Street View. From there I grabbed the coordinates. In order to identify the general area, I used either the aformentionned article, my own relative knowledge of Paris for the most famous places, hints from the shots themselves (some of them have the street name literally written), or asked people around when I was stuck.

Identification of shot No. 31. Circled in green are the Archives Nationales. Here is a link to the Google Earth position (Chrome only).

By far the most challenging location to find was shot number 31, which is a shot of rooftops. Google, family, or friends could not help me with this one. I eventually spent an evening browsing Google Earth with 3D buildings activated, searching for a dome similar to the one at the top of the shot, and identified that it was a shot of the Archives Nationales, taken from the Centre Pompidou.

Here is a spreadsheet listing the locations of each of the 60 shots. The map below contains one marker for each of those 60 locations. As you can see, the shots clearly doesn't cover most of Paris. Almost all of them are from the Right Bank (North of the Seine), for starters. Blue markers are daytime shots; red markers are nighttime shots.

Using this map, I grouped the locations into "clusters" which are easy to cover on foot. Each cluster can then be linked either by subway, by foot too, or just be photographed another day. So here are the "walks" that I eventually scheduled:

Area	Shots
Montmartre	5, 19, 9, 18, 4, 31
Parc Monceau	48, 50, 49
Champs Elysées	21, 35, 23, 12, 39, 36, 2
Tour Eiffel	30, 17, 15
Concorde	7, 6, 26, 1, 28, 3, 32, 14, 13, 24
Opéra → Louvre	38, 29, 16, 34, 27, 8
Saint Michel / Notre-Dame	20, 37, 47, 46, 42, 41, 40, 43, 44, 10, 45, 25, 11, 22, 33
Night Shots	51-60

Photography

I took pictures and videos with a Panasonic FZ200. The only other equipment I had was my smartphone with locations on Google Maps and snapshots from the movies to imitate framing. When I started photographing, I immediatly unndertood that I had made a mistake by doing this project in July because 1/ there are way too many people and 2/ there is way too much light.

Initially I did not intend to take videos to actually recreate the sequence, but only to take pictures to create an equivalent photo album. As I started shooting, I realized that my pictures were way pooreer, photographically speaking, than the lovely shots in the movie, due to the poor light and my lack of equipment and skills. So I decided to take videos to recreate the full sequence, such that even without the photography magic, the project would at least have a interesting and vivid output. My camera, the Panasonic FZ200, comes with native 1080p video. Although the image is not of great quality, it does the job.

I also realized that constraining myself to the shots of the movie was actually very limiting. I thought that imitating the composition of those shots was an easy thing to do, I just had to "copy", but because of all the various factors that changes between the movie and the reality (not the same light, not as many people, cars parked in the way, not the same overall "mood", etc), recreating the exact shots of the movie was not necessarily the best choice for optimal photograhic result. This is why I adapted the framing for many shots. Also, sometimes the exact spot to take the picture was simply not the convenient place to be.

There are 5 shots out of the 60 that I substituted for other ones:

Shot No. 12 of the Fouquet's terrace. Since the restaurant has been burned during the yellow vest protests, there was no terrace at all. I replaced it by the entrance to the metro Cluny-La Sorbonne near Saint Michel. I also modified the point of view of Shot No. 23, of the Fouquet's entrance, so that it shows the Fouquet's renovation work.
Shot No. 20 of a flower shop at rue Edouard Colonne. The shop is now closed and the whole building facade is covered in scaffholding. I replaced it with a shot of rue Rembrandt near the Parc Monceau, a pretty little street with a lot of green foliage.
Shot No. 27 of the Louvre pyramid, with the camera pointing West. The spot was closed off in preparation of a festival, so I replaced it with a shot of the pyramid with the camera pointed East, that is, towards the Palais du Louvre.
Shot No. 31 of rooftops. It is either taken from the back of the Centre Pompidou or a rooftop nearby, none of which are publicly available (I admit I did not physically check the point of view from the café Georges, but I'm almost sure the angle is unavailable even from there). I replaced this shot with another shot of rooftops taken from Montmartre.
Shot No. 50 of a statue in the Parc Monceau. I waited 1 hour to take it, before abandoning. People sitting on the benches. Then people doing their yoga class. Then children playing around. I replaced it with another statue from the same park at a quieter spot.

When you're trying to do a photo project but you remember your camera is a superzoom

For each shot, I took the picture in Aperture mode, with the lowest aperture available, to limit light and to have a depth of field as long as possible. My camera also has a built-in "HDR mode", where it rapidly takes multiples shots, each with a different exposure, before blending them together. Since lot of shots contains harsh contrasts (e.g. shaded facades vs. bright sky), HDR mode came in handy, although it behaves badly with movement because of the delay between each exposure (the blending algorithm can then yield weird outputs). The final album contains either the HDR picture if exploitable, the Aperture one otherwise. I took some of the night-time pictures in Manual mode, as in any other mode the camera was trying too hard to get a "normal" exposure, which overblown artificial lights.

Editing

The first post-treatment that I applied to the videos was to stabilize them. Since I had no tripod, most of the videos contained a fair amount of micro-shaking, as well as some soft macro-movement. I stabilized the videos using ffmpeg and the libvidstab filter, following this tutorial. Here is an example command line to stabilize a video:

ffmpeg -i /home/valentin/Pictures/Midnight_Sorted/57/P1010379.MP4 -vf vidstabdetect -f null -
ffmpeg -i /home/valentin/Pictures/Midnight_Sorted/57/P1010379.MP4 -vf vidstabtransform=smoothing=30:input=transforms.trf /home/valentin/Pictures/Midnight_Sorted/57/P1010379_stab.MP4

This eliminated the micro-shaking but left some smooth overall movement, which I don't find annoying so it's okay. One side effect I noticed from stabilization was a cropping of the videos, which was problematic for shot No. 41 of the UGC Danton theater, where part of the emblem "UGC Danton" was cut out of the frame, so I exempted this shot from stabilization. Another side effect was a sort of "distortion" effect on the whole picture, which can be noticed on shot No. 5 of the Moulin Rouge. I did not worked around this, but it is rather subtle and way better than shaking.

I put the shots together using Shotcut. Although I followed relatively closely the editing of the movie, my final edit is not a frame-perfect recreation.

Reading notes: July 2019

2019-08-03T00:00:00Z

The Guardian: Super-tall, super-skinny, super-expensive: the 'pencil towers' of New York's super-rich

New York City has FAR (Floor Area Ratio) regulations for residential buildings. The FAR is how much living area you're allowed to have in your building as a function of the parking lot area. So with a FAR of 10 you can make a 10-storey building over the entire surface of the parking lot. However if you only make your building half the size of the parking lot then you're allowed to make it a 20 storey building. In Manhattan, the FAR value varries according to the specific area.

Then there are TDR (Transferable Development Rights). If one building doesn't exploit all of its allowed surface according to its FAR, the owner can sell the remaining surface to an adjacent building, which is then allowed to surpass its own limit with what he has bought from his neighbor.

Real Estate magnats in NYC are making deals to transfer livable surface from one adjacent building to another, bubbling up to gigantic residential skyscrapers, which also happen to be very thin so as to maximize height according to FAR. The current top example is 432 Park Avenue at 425.5 meters. More are being built or scheduled to be built. Since FAR only specifies the allowed livable space, they also add "technical floors" to add some free height. Appartments in those buildings are sold for extreme prices to millionnaires or billionaires, who don't live in them since it is merely an investment.

Some people are worried that such tall skyline will cast vast shadows to Central Park. Pro-tall-skinny-buildings counter-argument is that the total amount of allowed height is finite, and what happens is just a specific concentration of height, which might actually be preferable to what would be a uniform height, because skinny shadows move faster throughout the day than bulky shadows.

New York Times: Notre-Dame came far closer to collapsing than people knew. This is how it was saved.

The firefighters were called 30 minutes after the fire was detected, because the guard who went to check for the fire went to the wrong building. It is not clear whether it is because the agent who monitored the alarm misunderstood the cryptic output of the alarm UI, or gave the wrong direction, or the guard misunderstood the direction over the radio. The warning system consisted of 160 detectors and required dozens of experts to design over 6 years. Before the firefighers arrived smoke started to be visible from the outside, and the information was on Twitter.

At the begining, firefighers went up the stairs of the cathedral to fight the fire directly from the attic. They later retreated because it was unstoppable, but made the the observation that the wind was bringing the fire towards the North tower. The tower holds 4 huge bells, each of which are hung on wooden beams. The fire would have set the bells lose, and considering their significant weight, their fall could potentially have damaged the tower to the point of collapse.

The general supervising the situation declared that the attic was lost, and that efforts should be focused on saving the towers, especially the North one. A team of firefighers were sent on a commando mission (the most dangerous move of the night) to reach the North tower from the South tower, put the fire out, and than come back using the South tower too, which they successfully did because they're badass as hell.

Time: Elon Musk Told Us Why He Thinks We Can Land on the Moon in 'Less Than 2 Years'

Elon Musk says SpaceX could send a man to the Moon in two years if they wanted to. When asked about sending a man to the ISS, he says it acts like the Arrow paradox: everytimes they're half-way launch, they still need to cover the second half.

The One Is Two Society

2018-10-13T00:00:00Z

If I wanted to waste time and energy, I could create and promote the "One Is Two Society", an organization defending the idea that mathematics is wrong and that 1 = 2. The main argument would be as follows:

(1) Let have two equal integers: a = b
(2) Multiply by a:               a² = ab
(3) Substract b²:                a² - b² = ab - b²
(4) Factor both sides:           (a - b)(a + b) = b(a - b)
(5) Divide by (a - b)            a + b = b
(6) Because a = b:               2b = b
(7) Divide by b:                 2 = 1

If I was advertising my society well enough, I think I would gather a fair number of members. In fact, I would gather anyone for whom the following criteria would be true:

Curious enough to follow a mathematical demonstration
Not good enough at math to spot the mathematical error (division by zero at step 5)
Paranoiac and narcissist enough to think that it's possible that a little organization in his own corner must be right against what is teached at school, what is common knowledge, and what is written in every encyclopedia as being knowledge backed up by centuries of maths being based on it.

Criteria 1 is relatively easy to check; although math isn't the cup of tea of all, still many people are curious enough to follow the demonstration, and good enough to understand it. Criteria 2 is the easiest to check; the vast majority of people don't spot the error. Once the demonstration reaches an absurdity, we know there must be an error, but most of us don't spot it in a first place, and it's hard to point out of the exact problem even once we know there is an error.

Criteria 3, however, is the one that is hard to check. It's the one criteria that would make my society a marginal movement and not a widespread misunderstanding. Once the demonstration reaches 2 = 1, the vast majority of people think "Ah! This is wrong. Where is the error?". Only some tiny class of people, fanciful enough, will think "Oh! I've been shown that maths are broken! 1 = 2 !!"

The fact that criteria 3 is the one making the difference is very important, because it means that the existence and relative popularity of my society wouldn't be a literacy issue regarding mathematics, it would be a trust issue regarding culture.

I believe that the relative popularity of modern flat Earth society can be explained with the same mechanism. When the flat-earth subject is brought into discussion, I notice that a lot of people consider that flat-earthists must be stupid or very ignorant of science. However if you look at the flat-earth literature, you realize that some of them are quite knowledgeable about the history of science related to Earth, and their fallacies can be hard to dismiss properly. It would be time consuming to properly break every one of their arguments, but we don't need to do so because we already know from culture that Earth isn't flat. From the point of view of a single individual, as soon as you remove the trust in culture, acquiring reliable knowledge of the world becomes way more complicated, and cunningly error-prone.

Exhibit 1: Bedford Level Experiment

One of the major argument from flat-earthers is the Bedford Level Experiment. The idea of this experiment is first to go to a long straight of water (we want a long, level, surface). On this long straight, regularly mount vertical shafts with a red mark always at the exact same height from the surface of the water (we can use boats or buoys to mount them), each shaft relatively far away from each other. Now go some distance away along the straight and look at all the aligned shafts with a telescope.

If the Earth is truly rounded, then, viewed from the telescope, the series of red marks shoudn't be aligned vertically. If they are aligned vertically, then it means that the Earth is flat. Given the radius of the Earth that is claimed by science, specific distances to respect between the marks can be calculated so that a vertical misalignment would be clearly visible.

So the flat-earthers found the perfect river to perform this experiment: the Old Bedford River, in England, which contains a perfect 10 km straight. They did the experiment, and guess what, they viewed that all the marks were aligned, therefore proving that Earth is flat.

Now, confronted with such demonstration, as a simple citizen, you have two ways to react:

You can point out that the experimental protocol is invalid, because air refraction along the straight will mess around the marks alignment from the viewpoint of a far-away observer. This is a slippy argument, because it involves science and science is complicated. A flat-earther would probably counter with "Yeah but what is the probability that the all the marks becomes aligned after being refracted?" and then you would have to do study the subject and do all sorts of calculations and unless you know your stuff you'll lose the debate.
You can accept the fact that science and experimentation are delicate, error-prone things that should be carried out by professionnal, and your money is therefore on the worldwide consensus instead of the guys who went on an obscure trip to an England river. This is based on trust of science, not science itself, and you will win the debate with this.

Exhibit 2: The Flat Earth Wiki

The Flat Earth Wiki is a fascinating piece of misinformation. It exhaustively rebuts each and every argument for a round Earth in a seemingly scientific way, and constitutes as a whole a incredible corpus of fantasy science.

My favorite article is Universal Acceleration. It rebuts the argument that since there is gravity on Earth (we don't levitate away yo), the planet should naturally arrange itself as a ball around a then-defined center of gravity. But that not how it goes in flat-earth land. In this world, the Earth is a disk, which is constantly accelerating "upwards" through the Universe, giving the illusion of gravity.

The worst is that they back it up with some general relatively, rightfully so: in general relatively, the equivalence principle states that it's impossible to make the difference between acceleration and gravity. For example, would you be in an accelerating spaceship, therefore pushed towards the back of the spaceship, any observable effect would be similar to gravity in this spaceship.

Then you may ask how can something be accelerating constantly, since this means it would gain more and more speed, and one day it will reach and surpass the speed of light, which is impossible. But, hey, they've got you here, with some equation and Lorentz factor and whatnots, and I know that some weird stuff happens near the speed of light, but I'm not knowledgeable enough about it to confirm or disprove their calculations. Yet, again, I don't need to do so, because I know from culture that it isn't true, and therefore that their calculations or reasoning must be wrong. (Anyway if the Earth can be flat, I don't see why the speed of light couldn't be surpassed.)

Although in this article I defend the value that there is in trusting science, by no means I want to discourage the understanding of it, quite the contrary. Understanding how it works and why it works is the best way to further solidify trust you can put on it. However, it is a very time consuming process and we don't always have the interest or energy to do so, hence, in my opinion, the need to have a guideline to follow that one must be able to trust.

On a related note, there is a Quora answer by physicist Richard Muller where he explains that global warming skeptics also are well equiped with ammunitions about the subject (certainly in a way more reasonable and less far-fetched way than flat-eathers, the subject being more subtle), and that you shouldn't get involved in a debate with them unless you know your stuff very well.

The Meaning of It All: Thoughts of a Citizen Scientist

2018-09-29T00:00:00Z

I've been reading The Meaning of It All from Richard Feynman. It's a collection of transcripts of lectures given by Feynman at the University of Washington, Seattle, in 1963. In those lectures, Feynman discusses the relationship between science and society in an informal way.

I will simply quote two excerpts from the lectures, about skepticism, which struck me as particularly interesting. The first one is:

Why do we grapple with problems? We are only in the beginning. We have plenty of time to solve the problems. The only way that we will make a mistake is that in the impetuous youth of humanity we will decide we know the answer. This is it. No one else can think of anything else. And we will jam. We will confine man to the limited imagination of today's human beings.

Feynman opposes dogmatic explanations to the unknown. What I like very much in this argument is that what appears to be most of a concern to Feynman isn't so much that such dogmatic explanations would likely be unreliable and incorrect, but most importantly that they will be boring, because limited to the concepts that we can conceive at humanity's current state of knowledge.

A famous quote from Feynman is "I think nature's imagination is so much greater than man's, she's never going to let us relax." The peculiarities of Nature is a leitmotiv throughout all of Feynman's literature, and I think this point of view explains the enthusiasm and sense of wonder he conveys so well when talking about physics.

The second excerpt is about the death of his wife:

I met a girl at about thirteen or fourteen whom I loved very much, and we took about thirteen years to get married. It's not my present wife, as you will see. And she got tuberculosis and had it, actually, for several years. And when she got tuberculosis I gave her a clock which had nice big numbers that turned over rather than ones with a dial, and she liked it. The day she got sick I gave it to her, and she kept it by the side of her bed for four, five, six years while she got sicker and sicker. And ultimately she died. She died at 9:22 in the evening. And the clock stopped at 9:22 in the evening and never went again. Fortunately, I noticed some part of the anecdote I have to tell you. After five years the clock gets kind of weak in the knees. Every once in a while I had to fix it, so the wheels were loose. And secondly, the nurse who had to write on the death certificate the time of death, because the light was low in the room, took the clock and turned it up a little bit to see the numbers a little bit better and put it down. If I hadn't noticed that, again I would be in some trouble. So one must be very careful in such anecdotes to remember all the conditions, and even the ones that you don't notice may be the explanation of the mystery.

So, in short, you can't prove anything by one occurrence, or two occurrences, and so on. Everything has to be checked out very carefully. Otherwise you become one of these people who believe all kinds of crazy stuff and doesn't understand the world they're in. Nobody understands the world they're in, but some people are better off at it than others.

What I like about this one is that Feynman doesn't try to proclaim being some sort of infallible rationale being, as it is often the case in the skepticism community, whose members often end up being quite arrogant to others. It's a very personal example where he illustrates how one can be tempted into reading "signs" on events which have a pretty logical explanatio, and how tricky it can be to actually find this explanation. I find it to be simply and humbly told.

Let's not forget about SNI

2018-08-11T00:00:00Z

Mozilla is launching one of their "shield studies" (experimental features they push on Firefox Nightly or some low percentage of regular Firefox's users) which consists in using DNS over HTTPS with Cloudflare's DNS (1.1.1.1) by default.

As for anything over HTTPS, DNS over HTTPS (DoH) brings two guaranties:

Encryption: nobody can spy on the domain name being resolved between you and the resolver
Authenticity: the result of the DNS query has not been altered in transit between the resolver and you

The reason Mozilla uses Cloudflare as the default provider is firstly because in order for DoH to work, the resolver must support it, which isn't the case for many default ISP's own resolvers (used by default by most users), and secondly because they think ISPs cannot be trusted whereas Cloudflare should be: they link this page, by stating that it constitutes a "very strong privacy agreement", which seems legit since there literally is the word "promise" in it. Forgive my skepticism, but I find this part of Mozilla's argumentation rather clumsy. A recent blog post shares my doubts.

What everybody seems to forget about, however, is that in any case ISPs can still spy on the domains their users connect to. When a browser wants to start an HTTPS connection with a server, first the IP of the domain is resolved (using DNS, or DoH, as it happens), then the browser asks the server for its certificate (some data which proves that the server really is the one it says it is) using the resolved IP to route the request. However, since multiple domains can be hosted behind the same IP address, and a certificate only validates one domain, the browser must send the domain alongside the IP, so that the server can know what certificate to answer with. All of this passes through the user's ISP in clear.

This is called Server Name Indication (SNI), and you can read more about it in this very good StackOverflow answer. As you may guess, some users on Reddit already made the remark, as well as on Hacker News.

In conclusion, even if ISPs would be considered less trusted than a centralized provider, using a centralized DNS provider doesn't quite solve the problem since the domain are still sent in clear to the ISP. Although extracting the domains from TLS handshakes might be technically more complicated than just looking at DNS logs, if we're assuming malicious ISPs in a first place, there is no reason they wouldn't do it.

Timing a simple Python command-line tool

2018-08-05T00:00:00Z

I programmed a little todolist tool for the command line, and I'm not entirely satisfied with its "performance". What bothers me is that I can notice a tiny delay between the moment I hit the todo command and the moment the output is written to the standard output. So I analysed how much time it took, and where the time was lost. My initial intuition was that most of the time was due to querying a SQlite database, but I was very wrong.

Note that any performance number given in this article comes from an entry-level Intel Pentium-powered computer. The program is faster on my newer laptop. All the measurements are about using the bare todo command which simply prints the list of pending tasks

Total time

To time the program, we can use the UNIX's time program:

$ time todo
[...]
real    0m0.097s
user    0m0.078s
sys 0m0.016s

It takes 97ms for the todo command to execute, hence the very little, but noticeable, delay. As a comparison, cat-ing a ~200 lines file takes about 6ms. So 97ms to print a bunch of tasks is really slow in absolute terms.

Script time

To investigate further, we need to use the cProfile Python module, which will break down the time taken by each function call and each module import. cProfile can be used as a stand-alone executable thanks to the -m Python interpreter's flag. We're sorting the function calls by cumulative time (meaning if a function is called multiple times then all those times are summed together) descending:

$ python -m cProfile -s cumtime ./todo.py

     34229 function calls (33095 primitive calls) in 0.050 seconds

 Ordered by: cumulative time

 [...]

The important information here is that cProfile tells us that the code has been executed in 0.050 seconds. We are missing 47ms to be consistent with the 97ms total time. Well, surprise, those 47ms are actually the time the Python interpreter takes to start up, before even starting executing the script. This can be verified by timing the interpreter while it executes the empty program:

$ time python -c ''
real    0m0.045s
user    0m0.028s
sys 0m0.012s

45ms. Checks out with a little margin of error.

That is very bad. It means that almost 50% of the total time it takes for the program to run is due to Python starting up, which is a contextual aspect out of my control.

Let's analyse the other 50%.

Main time

I now look at the listing of function calls, sorted by cumulative time, descending (I've removed lines containing Python internal stuff):

 ncalls  tottime  percall  cumtime  percall filename:lineno(function)
      1    0.000    0.000    0.050    0.050 todo.py:3()
      1    0.000    0.000    0.028    0.028 todocore.py:120(main)
      1    0.000    0.000    0.021    0.022 todocore.py:36()
      1    0.000    0.000    0.012    0.012 docopt.py:493(docopt)
     35    0.000    0.000    0.010    0.000 re.py:277(_compile)
      1    0.000    0.000    0.010    0.010 todo.py:527(feedback_todo)
     29    0.000    0.000    0.010    0.000 todo.py:676(safe_print)
      1    0.000    0.000    0.010    0.010 subprocess.py:356()
     22    0.000    0.000    0.010    0.000 sre_compile.py:563(compile)
     23    0.000    0.000    0.009    0.000 re.py:221(compile)
      1    0.000    0.000    0.008    0.008 docopt.py:40(fix)
      2    0.000    0.000    0.007    0.003 todo.py:595(get_basic_task_string)
      2    0.000    0.000    0.007    0.003 todo.py:612(get_task_string_components)
      1    0.000    0.000    0.006    0.006 configparser.py:119()
      2    0.000    0.000    0.006    0.003 todo.py:683(get_datetime)
   1660    0.001    0.000    0.006    0.000 docopt.py:34(__eq__)
   42/1    0.001    0.000    0.006    0.006 docopt.py:45(fix_identities)
     22    0.000    0.000    0.006    0.000 sre_parse.py:750(parse)
  53/22    0.000    0.000    0.006    0.000 sre_parse.py:363(_parse_sub)
      1    0.000    0.000    0.004    0.004 dbapi2.py:23()
      1    0.000    0.000    0.002    0.002 datetime.py:5()
  [...]

A bit a guidance here:

The cumtime is the column we're interested in
The filename:lineo(function) is the column giving us the performance culprits. In this last column, module imports are marked with the conventional name <module>. A module import is simply the source code from this module being executed from top to bottom (with the side-effect of its top-level variables being binded as attributes of the object the module is being imported as)
The first line is always the execution of the overall script (no different than importing it: execution from top to bottom) and therefore takes the entire time measured
The only thing that todo.py does is importing todocore.py, and executing its main function. The only thing that todocore.py does is importing libraries and defining functions.

The important information here is that the main function takes 28ms to execute. We are missing 22ms to be consistent with the overall 50ms execution time. Those 22ms are in the importation of todocore.py, which is not satisfying, because todocore.py does nothing. It imports libraries and defines functions. Well, turns out that in Python, importing libraries isn't nothing at all.

If we grep the previous listing with <module> to filter imports only, then we end up with:

    1    0.000    0.000    0.021    0.022 todocore.py:36()
    1    0.000    0.000    0.010    0.010 subprocess.py:356()
    1    0.000    0.000    0.006    0.006 configparser.py:119()
    1    0.000    0.000    0.004    0.004 dbapi2.py:23()
    1    0.000    0.000    0.002    0.002 datetime.py:5()

The first line is the root import of todocore.py (22 ms) and the remaining lines are modules from the standard library, whose import's performances together sum up to the root 22 ms.

So, 75% of the execution time has nothing to do with my program. The first 50% is the interpreter starting up, and then 25% is due to importing stuff from the standard library. Any optimization that I can do on my code will be bounded under ~25% of the overall execution, that is 28 ms.

In fact, I found that imports can be somewhat optimized. In my case, there is one import that is different than the others: subprocess is only actually used for a very specific use-case which is to open a text editor when the user wants to edit a task. In Python, you don't necessarily have to do imports at the top of the script, you can do them inside a function. This means that I could avoid to systematically import subprocess, and only import it when necessary instead. This made me win 10 ms.

Business Logic time

Near the top of the listing, there is an important function call that takes quite some time:

    1    0.000    0.000    0.012    0.012 docopt.py:493(docopt)

docopt is the function that parses the command-line arguments. It takes 12 ms out of 28 ms total in main. The command-line in question being: todo. In absolute terms, such performance is quite ridiculous.

So, finally, after the interpreter starting up, after the imports being done, after the command-line being parsed, my code, at last, executes in 16 ms.

The point of docopt is that you define the documentation of your command-line interface, and it automatically generates a parser for it (the opposite of e.g. the standard argparse that generates a documentation from a parser you build with its API). I studied a bit the performance of docopt and realized that a big performance hit was to parse the documentation text and build the parser from that. Once the parser is built, parsing the command-line is fast. This is sad, because the internal Python object representing the parser could be literally hard-coded in the source code, instead of being generated once again from the text everytime the program is invoked.

I though I would win some time by using the standard argparse since it builds a parser programmatically and doesn't have to parse text, but after experimenting I found out that I was wrong. With argparse, you add a command that your parser is able to parse with the add_argument method, and this method took 1 ms to execute. So since my program has more than 12 commands, it was slower than docopt's 12 ms.

Looks like parsing command lines is hard. How the hell does git even work out.

I didn't investigated much further into the business logic, because it's all broken down in little pieces of a few milliseconds or less that together sum up to the 16 ms. There is the notable 7 ms contribution of the function get_task_string_components, which, I found out, was so slow because some tasks in todo's output contain a deadline alongside their label, and Python is slow to convert an internal datetime object to a string representation when using the strftime function and a date format. You can make it an order of magnitude faster by doing it yourself with basic string formatting.

I searched for the fetch_all function, which is the function from the sqlite3 library that actually performs the query on the sqlite database. This was my initial intuition for the bottleneck. It was deep down the listing, with a cumtime of "0.000", which means it executes under half of a millisecond.

Conclusion

This was a toy analysis on my toy program, but I get valuable lessons from it:

You can very wrong about the bottleneck. You should measure.
If you want it to be snappy, you should use a compiled language
If you really want to be serious about optimization, then you'll most likely need to abandon standard stuff and implement yourself the stack of some specific paths all the way to the bottom

No. 3 makes me wonder: when you do a Google Search, from your browser all the way to Google hardware, what is the percentage of it that is standard, and what is the percentage of it that is custom-made?

How to encrypt messages on Linux

2018-04-09T00:00:00Z

Disable Bash history:

unset HISTFILE

Encrypt:

echo 'your string here' | gpg -c | base64

Decrypt:

echo 'encrypted here' | base64 -d | gpg -d

Both commands will open a graphical prompt for the password.

Do not use query string parameters for cache busting

2018-03-25T00:00:00Z

When you want to refresh some static resource that might have been cached by caches you don't have control over, you have to change the URL of the resource so that those caches won't serve the obsolete version, a practice known as cache busting. One way to bust cache is to use a version number in a query string parameter when referencing the resource.

For example, if your HTML uses theme.css:

<link rel="stylesheet" type="text/css" href="theme.css">

and that, for some reason, you lose control over cached versions of the stylesheet (e.g. the stylesheet is served with the HTTP Cache-Control: public header along with an aggressive max-age that will make caches all over the wire cache it for a long time), then you can always "bust" the cache by serving this new link:

<link rel="stylesheet" type="text/css" href="theme.css?v=2">

This changes the URL of the stylesheet, meaning caches won't serve the old version. Other variants include renaming the file (theme.v2.css) or renaming the path of the file (/v2/theme.css). However those variants are a bit more complicated to implement because they require to rename the files before deploying, whereas the query string method only requires to update the reference in the HTML, since static servers simply ignore query string parameters.

You shouldn't, however, use the query string method, for the following reason: if at the moment you're serving theme.css?v=2 anyone on the Internet issues a GET request to theme.css?v=3 then caches will associate the v3 to the content of the v2. When you will want to deploy a new version and will update the query string parameter, you'll see that the resource doesn't update. A malicious client could be even more vicious and query something like theme.css?v=6 when you're at v=3 to let you see how well the system works until a few days when, updating from v=5, you try to deploy v=6 and witness the resource going back in time to its state as it was at v=3.

Using a version number in the filename is much preferable, for the simple reason that if someone requests theme.v2.css when you're serving theme.v1.css, the server will respond with a 404 error and no content, which is of course not a cacheable response.

Nessun Dorma in Rogue Nation

2018-03-14T00:00:00Z

In Mission Impossible 5: Rogue Nation, one of the main action scenes takes place at an opera in Vienna, during a representation of the opera Turandot from composer Puccini. This scenes features one the most famous theme of this opera, Nessun Dorma. It's a very famous theme that probably evokes something even for those (like me) who doesn't listen much to classical music.

At the end of the movie, during an emotional moment, the same theme can be heard in the soundtrack of the movie itself, although timidly. Here are two YouTube links with the corresponding timestamps so that you can compare:

I find this is a really nice touch from the film soundtrack composer Joe Kraemer.

2018 Oscars Predictions

2018-02-25T00:00:00Z

Here are my predictions for the winners of the 2018 Academy Awards, whose ceremony will take place next Sunday.

Category	Prediction
Best Picture	Lady Bird
Best Director	Christopher Nolan (Dunkirk)
Best Actor (leading)	Gary Oldman (Darkest Hour)
Best Actress (leading)	Frances McDormand (Three Billboards*)
Best Actor (supporting)	Sam Rockwell (Three Billboards*)
Best Actress (supporting)	Allison Janney (I, Tonya)
Best Original Screenplay	Three Billboards*
Best Adapted Screenplay	Call Me by Your Name
Best Original Score	Phantom Thread
Best Visual Effects	Blade Runner 2049
Best Cinematography	Blade Runner 2049
Best Animated Picture	Coco

* Three Billboards Outside Ebbing, Missouri

Git branches and slashes

2018-02-11T00:00:00Z

I've found out that using slashes to name git branches in a hierarchy fashion is limited to only one level:

$ git checkout -b feature/public-api
Switched to a new branch 'feature/public-api'
$ git checkout -b feature/public-api/oauth2
fatal: cannot lock ref 'refs/heads/feature/public-api/oauth2': 'refs/heads/feature/public-api' exists; cannot create 'refs/heads/feature/public-api/oauth2'

The reason for this is that a git branch is simply a text file in the .git/branches directory, containing the hash of the commit at the tip of the branch. When a branch's name contains a slash, git creates a subdirectory to store this file in. So the hash of the branch feature/public-api is stored at .git/branches/feature/public-api. If you try to add one more level to that, then git will try to create the .git/branches/feature/public-api directory, which is impossible, because there's already a file with this name.

It's yet another leaky abstraction from git, once again for the purposes of performance and simplicity of implementation, which I can understand.

The Social Network and "We need to expand"

2018-01-28T00:00:00Z

I recently watched The Social Network yet another time. I noticed something in the film that I hadn't in my previous viewing.

There is a scene in the movie where Mark Zuckerberg is in a bar and notices that his ex-girlfriend Erica Albright is having a drink with her friends. He goes to her and ask her for a few minutes in private so that they can talk. Erica declines; she basically is still angry about the mean things he has written about her on his blog after they broke up at the beginning of the movie. Mark repeatedly asks for a few minutes of private discussion, in spite of the rebuttals. He eventually abandons and joins his friend Eduardo, who thinks he has done the good thing of apologizing to her (which Mark didn't). Mark, seemingly still frustrated of the scene with Erica, only says:

We need to expand

In my previous viewings, I took this line as yet another random example of Mark switching subjects rapidly, making hard to track what he is thinking about. In my most recent viewing, however, I realized that the reason he suddenly wants to expand is because he has realized that it's impossible for him to talk to Erica in real life, but if Facebook becomes big enough, Erica will eventually become a user of it, and that will provide him with a way of reaching out to her through a medium he's comfortable with. He wants Facebook to expand because he wants it to become so big it's the default way of reaching out to someone, which is a long shot at bypassing his own communication problems in real life.

At the end of the movie, when Facebook has effectively became this big, Mark loads Erica's profile, which, as planned, exists, and sends her a friend request.

This reading of this line gives two important pieces of insight about Mark's state of mind during the movie:

How visionary he is. It must take some grand vision of his own project to see the possibility of it becoming this big in scope and popularity.
How concerned he is about his relationship with Erica. If this whole interpretation is correct, one of the reason he built Facebook was to talk to her. This is also hinted at in the dance-club scene where Sean Parker explains that the original reason he started Napster was to impress a girl. Mark then asks him if he sometimes still thinks about this girl, revealing that he, himself, sometimes thinks about Erica.

There's something weird in considering Facebook as a better way than real life to reach out privately to someone. First because social networks are known to be a place where people don't show their true selves, and second because the data collection from the company itself makes it not so much of a private space. When Mark abandons trying to talk to Erica, she says "and good luck with your... video game." Whatever he's trying to build, and no matter how addictive and popular it is, it's going to be artificial and won't stand up to reality.

Image orientation in the web

2016-10-28T00:00:00Z

I'm building a web gallery made for self-hosting. When I tested the first prototype of my gallery with my personal pictures, I immediately noticed that something was wrong with all the pictures in portrait format: their orientation was wrong. It was odd, because any other mean of watching the pictures, such as my camera and my image viewer on Linux, rendered the correct orientation.

The reason the images were wrongly orientated is because my camera uses Exif data in order to encode the actual orientation of the image. Exif (Exchangeable image file format) is a collection of metadata such as GPS location, date and time, etc, about the picture that was taken, that is contained in the file, alongside the actual image data. The image is always stored in landscape mode, and the orientation is solely encoded in the Exif data.

This is not new nor bizarre. In the old days, camera did not know whether a picture was taken in landscape orientation or in portrait orientation (or upside-down) and people had to manually rotate their images on their computer. Then came cameras with orientation detection, which were able to tell how they were orientated while taking the picture. However, instead of actually rotating the image (that is, the content), such cameras simply indicated the orientation via the Exif orientation tag. All modern cameras do that, and most modern software knows how to read Exif data in order to display the proper orientation. Except browsers.

Actually, browsers know too. If you directly open an image in a modern browser, the orientation is correct. It's only when the image is embedded in a web page (via img) that the orientation might be wrong. Fortunately, there is a way to tell the browser to use Exif data to display the correct orientation, thanks to the CSS image-orientation property:

image-orientation: from-image; /* Use EXIF data from the image */

Unfortunately, as of today, this is still an experimental standard, and it only works in Firefox. No joke. iOS Safari is a special case, as it doesn't support the property, but doesn't need to as it honors Exif by default. Overall, there is currently no reliable pure HTML/CSS solution to properly orientate pictures in a web page according to Exif data.

Even if we accept the lack of support for image-orientation, its specification itself is bizarre. By default, Exif orientation is ignored. Shouldn't from-image be the default? To understand the current state of specification and of support, I've searched and read the Firefox bug tracker, the Chromium bug tracker and the W3C mailing list. More precisely, I've found the following threads quite interesting:

Bug 298619 on Bugzilla: (exif) should consider using exif orientation flag when displaying JPEG images, reported in June 2005
Issue 56845 in the Chromium bug tracker: EXIF orientation is ignored, reported in September 2010
This thread in the W3C mailing list: [css3-images] honoring EXIF orientation from images, started in November 2011

The reason Firefox bug report is so well ahead of Chromium's one is because the Chromium project started in 2008 while Firefox had already a solid community in 2005. In fact when the Chromium bug was reported in 2010, Firefox hadn't made much progress on the bug since the third answer to the bug was posted in 2009 and was just trying to attract more attention to it.

Three main points can be extracted from these discussions:

Nobody had planned to implement the standard. As can be seen in the mailing list above, the W3C started worrying about Exif in 2011, after browsers started worrying about it for very practical reasons. Browsers had no plan to implement the standard. They flat-out ignored it until Exif became mainstream enough in order to cause "bugs".
The alert was raised by smartphones and email. The Exif-related bugs started to appear in emails because of photos sent directly out of smartphones. The iPhone started using the Exif standard quite early on, and people started sharing pictures by email directly with their phone. Since the "default" way people hold their phone is vertical, it means that many pictures exchanged by mail suddenly depended on Exif. For this reason, the Bugzilla bug tracker mostly worried about Thunderbird while the Chromium bug tracker mostly worried about Gmail.
Everybody feared breaking the web. A straightforward support for Exif orientation by default was considered out of question by all parties (browsers and W3C) because they thought it would break the web. The idea is the following:

Someone took a picture. The picture carries Exif data. Photographer opened the picture with a software application that doesn't understand Exif data and saw the picture badly oriented. Photographer manually rotated the picture so that it looked good. Picture is now inconsistent with Exif data. If the browser suddenly starts honoring Exif data by default, picture is badly oriented again.

As you can see, the scenario is based on the idea that the web contains a lot of pictures whose actual orientation is inconsistent with their Exif orientation. In such case, a support for Exif orientation can break sites that worked very well until the support was installed. However, there was no data to support such claim. Some people in the threads pointed out that the web might actually not contain so many such pictures and that not supporting Exif orientation might be causing more breakage than supporting it, but this opinion was mostly ignored.

As the fear of breaking the web related only to images embedded in pages, most browsers implemented partial support for Exif orientation: it worked when a picture was directly opened as a file, but not when it was displayed using img. The answer from the W3C to this compatibility problem was to allow developers to opt-in to Exif orientation via image-orientation: from-image;

With hindsight, it seems that many contributors in those threads weren't aware of how widespread the support for Exif was among cameras and among other types of photo viewers. As I said, they basically waited for the standard to become mainstream enough to cause bugs, and even then some of them were still questioning the relevancy of the standard.

I've honestly no idea whether supporting Exif by default would cause more damage on the web than the damage the lack of support is currently causing, but the fact is that today, browsers can cause bad surprises to web developers and seem to be quite late on the Exif game. Apparently Apple didn't wonder much about legacy when they honored Exif by default on their iPhones apps, maybe browsers should follow the lead.

As of today, the only way for a site such as my photo gallery project to store and display pictures properly is to rotate the picture according to the Exif orientation tag upon acquiring it (server-side), get rid of the tag, and then display the picture without any additional CSS. The web is basically living in denial of the Exif orientation standard, while every other piece of software is dealing with it.

Displaying colors in the terminal

2016-07-03T00:00:00Z

The next version of my terminal-based ToDo application will include colors. This article is a synthesis of what I learned from implementing this feature.

In the terminal, color is coded via escape codes. Colors are just a specific feature of many existing ANSI escape codes that enable various actions and formatting for the terminal. An ANSI escape code is a sequence of ASCII characters in the following form:

ESC[n1;n2;...L

where ESC is the ESCape ASCII character (#27), L is a letter indicating what kind of formatting to turn on, and n1, n2,... are parameters for the given action/formatting. For example, the letter A (resp. B) is the code for moving the cursor up (resp. down), and its only parameter indicates how many cells the cursor should be moved. To get a demo, you can open a terminal and type:

echo -e "\e[5B"

The prompt for your next command should appear down the first one with a few spare lines. The -e flag allow the interpretation of backslash escape, the \e escape corresponding to the ESC character. The quotes are necessary for the whole ANSI escape code to be interpreted.

All graphical-related codes come with the letter m, with the parameter(s) indicating what kind of formatting to apply. Since such escape code turns "on" the associated formatting for all text following, there's the special parameter 0 (escape code ESC[0m) which resets everything back to normal. Bash also resets everything when a command has terminated, so if you test escape codes with echo as in the previous example, you probably won't have to use the reset escape code manually.

I wish the first example I could give would be parameter 5 which enables blinking, but apparently it's not supported anymore by most terminals :-( (much like the HTML <blink> element isn't supported anymore by browsers. Maybe ESC[5m was implemented by an engineer being drunk too.)

So, I'll directly get to colors. There's 9 different parameters reserved for foreground colors (color of the text). Parameters 30 through 37 encode the 8 primary colors: black, red, green, yellow, blue, magenta, cyan, white. So, for a green hello world, you would type:

echo -e "\e[32mHello, world!"

These colors correspond to the colors you obtain when you "turn on" the components of the RGB coordinates. For example, black is (0, 0, 0), red is (R, 0, 0), magenta is (R, 0, B), etc. Since there are 3 components there are 2^3 = 8 primary colors. For some reason escape codes [30-37] render dark flavors of the colors. For example, red is only RGB(205, 0, 0)^[1]. Yellow is the most obvious one, you can try it yourself:

echo -e "\e[33mSupposed to be yellow!"

It turns out that if you mix colors with bold (parameter number 1), colors are pushed to their full intensity:

echo -e "\e[1;33mActually yellow!"

Then there's the parameter number 38. This one awaits other parameters after itself. Either one, either three. In the case of three additional parameters, those parameters indicates the RGB coordinates of the color. So-called "true colors" are only supported by some advanced terminal emulators, but not by xterm^[2]. You can try it out with yellow again:

echo -e "\e[38;0;255;255mActually yellow!"

In the case of only one additional parameter, this parameter should be a number between 0 and 255 (included) corresponding to a color in the 256-colors palette. Now, what is "the 256-colors palette". Well, while there isn't one unique standard to store colors in only one byte, xterm comes with its specific palette which you can find here. It seems that 256 colors are supported quite widely.

This is how this palette work:

Codes in the range [0;7] are the 8 primary colors in dark mode (same as produced by the parameters 30 through 37 previously seen)
Codes in the range [8;15] are the bright version of the 8 primary colors (same as produced by parameters 30 through 37 mixed with bold)
Codes in the range [16;231] are all the other colorful colors (isn't that a nice term to designate non gray-level colors). Code 16 is (0, 0, 0) and then coordinates are incremented with regular steps. The first step is a 95 increment, then there are 4 other steps which are 40 increment. So it goes this way:


    16  (0, 0, 0)
    17  (0, 0, 95)
    18  (0, 0, 135)
    19  (0, 0, 175)
    20  (0, 0, 215)
    21  (0, 0, 255)
    22  (0, 95, 0)
    23  (0, 95, 95)
    24  (0, 95, 135)
    ...
    231 (255, 255, 255)

Codes in [232;255] are gray levels (R = G = B). It starts at (8, 8, 8) and increments by steps of 10, arriving at (238, 238, 238) after 23 steps.

Finally, there's parameter number 39 that sets the foreground color to its default. It can be used as a foreground-color-specific reset.

Parameters 40 through 49 define the same behavior, but for background color.

Links

[1] RGB values for the 8 primary colors in different environments

[2] List of terminal emulators supporting true colors

equitext

2016-03-28T00:00:00Z

I've never been satisfied with the vulnerability of substitution ciphers being the frequencies of characters in texts. My main concern is that it depends on the statistics of the language the message is written in. While languages such as English or French (and most natural languages I guess) sure have distinctive frequency distributions, we can imagine a language where letters appear approximately the same amount of time in written texts. In such case, a frequency analysis isn't feasible, at least on single letters.

While I'm no expert in cryptography, I think that this wouldn't mean that a substitution cipher isn't broken and I believe plenty of other attacks would still be possible. Brute force, to begin with. The 26 letters of the alphabet offer 26! possible substitution keys. That's 12 orders of magnitude less than 2^128 yet 128 bit keys are considered weak by today's standards.

Anyway, out of curiosity I cogitated about a method that would take a text and somehow transform it in order to produce another text in which every character appears the same amount of time. I ended up with a text-to-text encoding for which I've written an implementation in Python in a module called equitext. Here's a demo:

>>> import equitext
>>> message = "A histogram is a graphical representation of the distribution of numerical data. It is an estimate of the probability distribution of a continuous variable (quantitative variable) and was first introduced by Karl Pearson."
>>> equitext.histogram(message)
  ======================================================================== 0.145
i ================================================= 0.1
a ================================================= 0.1
t ============================================= 0.09
r =============================== 0.063
o ============================= 0.059
e ============================= 0.059
n =========================== 0.054
s ======================== 0.05
b =============== 0.032
u =============== 0.032
d ============= 0.027
l ============= 0.027
f =========== 0.023
h ========= 0.018
c ========= 0.018
m ====== 0.014
v ====== 0.014
p ====== 0.014
y ==== 0.009
g ==== 0.009
. ==== 0.009
) == 0.005
A == 0.005
q == 0.005
w == 0.005
I == 0.005
P == 0.005
K == 0.005
( == 0.005
>>> encoded = equitext.encode(message)
>>> encoded
' ImobKAfgh)levscPwtp.(ydarnqui mrqolb(fevItu.npgiwyasAdch)KP sdc.pqrAnmihtaovfuKegw)lbIP(y huynbqo(iswlfIr.eP)gmtAapvKcd oKyahgsmwe)ntfuIip.PlrvqAd(bc (tawq.vAcplugI)mfsndyoirbPeKh( aeifnrPvtdhqwImgpylu.cb)AKos(.PwtsIboufmipKeAahv gn)yqldrc grPKIvil(dyA)s.hcpuqtbmaeofwn oKs(c)AgP.uhevIlqarmtpwnfydbi vwmhKqlrbf()ietopysPc.IudngAa'
>>> equitext.histogram(encoded)
. ======================================================================== 0.033
m ======================================================================== 0.033
) ======================================================================== 0.033
b ======================================================================== 0.033
r ======================================================================== 0.033
( ======================================================================== 0.033
  ======================================================================== 0.033
v ======================================================================== 0.033
h ======================================================================== 0.033
A ======================================================================== 0.033
c ======================================================================== 0.033
o ======================================================================== 0.033
t ======================================================================== 0.033
w ======================================================================== 0.033
n ======================================================================== 0.033
I ======================================================================== 0.033
y ======================================================================== 0.033
s ======================================================================== 0.033
u ======================================================================== 0.033
f ======================================================================== 0.033
P ======================================================================== 0.033
p ======================================================================== 0.033
g ======================================================================== 0.033
i ======================================================================== 0.033
K ======================================================================== 0.033
e ======================================================================== 0.033
d ======================================================================== 0.033
a ======================================================================== 0.033
q ======================================================================== 0.033
l ======================================================================== 0.033
>>> equitext.decode(encoded)
'A histogram is a graphical representation of the distribution of numerical data. It is an estimate of the probability distribution of a continuous variable (quantitative variable) and was first introduced by Karl Pearson.'

The encoded text is about 1.44 more lengthly than the original, although this depends on the size of the alphabet of the original text, that is, the number of unique characters it contains. 1.44 is the number for a message containing only letters of the alphabet. I explain this in the next part.

Two weeks ago I published an encrypted message on Reddit on the /r/codes subreddit. The message has been first encoded using equitext then encrypted by a substitution whose key is a permutation of the text's alphabet chosen at random. The post haven't get much attention, but someone nevertheless figured out interesting properties.

How it works

In a first time we'll assume that the text to encode is only made of letters of the alphabet, although the encoding works with any Unicode string.

The text is splitted in chunks of 18 letters (magic number explained in a few lines). Let C be a given chunk. C is one of the many possible combinations of 18 letters. We can define an index on such combinations. For example, 'aaa...a' would be combination number 0, 'aaa...b' would be combination number 1, and so on, all the way up to 'zzz...z' which would be combination number 26^18-1. Having such an index, we can say that C is chunk number N.

Meanwhile, we can also define an index on permutations of the alphabet. For example, the regular 'abcde...yz' would be permutation number 0, then 'abcde...zy' would be permutation number 1, and so on, all the way up to 'zyxw...ba' which would be permutation number 26!-1. Having such an index, we can take its Nth element, where N is the combination index of chunk C. We have then encoded a chunk to a permutation. We are sure that there are at least N permutations because 26^18 <= 26! Actually 18 is the greatest n such that 26^n <= 26!

The encoded text being a sequence of permutations of the alphabet, every letter has the same number of occurrences in it. That's all.

Since each chunk of 18 letters is encoded to a permutation (26 letters), the text grows by a factor 26/18 = 1.44

Efficient indexing

Finding the index of a given chunk is equivalent to a conversion from base 26 to base 10 where the number in base 26 is represented using letters of the alphabet. Encoding in one direction to the other is a straightforward base-to-base conversion.

Finding the permutation corresponding to a given index is a bit more involved. It's done using something called the Lehmer code. In the following paragraphs I try to give a friendly explanation of how it works. I begin by explaining how to find the index of a given permutation, then explain how to find the permutation of a given index.

There are 26! permutations. We can partition the set of permutations in 26 subsets. The first subset contains all permutations begining with 'a', the second one contains all permutations begining with 'b', and so on. It's trivial that all these subsets have the same size of 26! / 26 = 25! We can then decide that permutations belonging to the first set (the "a..." set) all have their index between 0 and 25!. The permutations belonging to the "b..." set all have their index between 25! and 2×25!, and so on, all the way up to the "z..." set whose permutations all have their index between 25×25! and 26!. Note that in these bounds given as examples, the upper bound is exclusive.

Once we've identified to what set a permutation belongs to, we perform the same process inside this set, except that we've removed the previous letter from the available letters. For example, inside the "b..." set, there would be the "ba..." set, with indexes between 25! and 25!+24!, then the "bc..." set with indexes between 25!+24! and 25!+2×24! (note that we've jumped from a to c since b is already consumed). We iterate over the letters of the permutation and go to the right subset at each iteration according to the letter we read. The final set is associated to only one possible index, which is the index of the permutation.

As you can see, finding the index of a given permutation is actually a simple computation. Let's dumb things down even more by considering that there are only three letters 'a', 'b' and 'c' in the ['a', 'b', 'c'] order and we want the index of the 'bca' permutation. This index is:

1*2! + 1*1! + 0*0! = 2 + 1 + 0 = 3

We take the ordinal of 'b' in ['a', 'b', 'c'] which is 1. We get the first term 1*2!
We take the ordinal of 'c' in ['a', 'c'] (we've removed 'b' from the list) which is 1. We get the second term 1*1!
We take the ordinal of 'a' in ['a'] (we've removed 'c' from the list) which is 0. We get the final term 0*0!.

The factorial number system

What's interesting here is that we have the decomposition of 3 in the factorial number system. The factorial number system is a system to write numbers where digits are coefficients of increasing factorial numbers instead of increasing powers. 3 is written 110 in "factorial base" because 3 = 1×2! + 1×1! + 0×0!

So how do you find the "factorial base" digits of an integer given in decimal base? Because that's gonna help us convert an integer to a permutation. Well, let's take 42. It's 13000 in factorial base. That's:

1*4! + 3*3! + 0*2! + 0*1! + 0*0!

Let's write that explicitly:

1*4*3*2*1 + 3*3*2*1 + 0*2*1 + 0*1 + 0

We can factor 1 from the first 4 terms:

1 * (1*4*3*2 + 3*3*2 + 0*2 + 0) + 0

Inside the inner-most group, we can factor 2 on the first 3 terms:

1 * (2 * (1*4*3 + 3*3 + 0) + 0) + 0

Inside th inner-most group, we can factor 3 on the first 2 terms:

1 * (2 * (3 * (1*4 + 3) + 0) + 0) + 0

Remember that this number is 42. From the way we've written it, it is now easy to understand how you can get its factoradic digits: if you divide 42 by 1 you end up with a remainder of 0 and a quotient of:

2 * (3 * (1*4 + 3) + 0) + 0

If you divide this by 2, you end up with a remainder of 0 and a quotient of:

3 * (1*4 + 3) + 0

If you divide this by 3, you end up with a remainder of 0 and a quotient of:

1*4 + 3

If you divide this by 4, you end up with a remainder of 3 and a quotient of:

If you devide this by 5, you end up with a remainder of 1 and a quotient of 0.

You stop there, and look at the remainders that you've accumulated: 0, 0, 0, 3 and 1. That's 3100 in reverse.

A convertion to "base factorial" is very similar to a convertion to a regular base: you recursively divide the quotient by the base until you reach 0 and the digits in the destination base are the remainders in reverse order. Instead that here, instead of "dividing by the base", you divide by increasing integers: divide by 1, then by 2, then by 3 and so forth.

Once we have the digits of an index in the factorial number system, it's easy to get its corresponding permutation. For example, let's take 3 (110) again with the ['a', 'b', 'c'] alphabet. You pop the letter with ordinal 1 from the alphabet: 'b'. The alphabet is now ['a', 'c']. You pop the letter with ordinal 1 from the alphabet: 'c'. The alphabet is now ['a']. You pop the letter with ordinal 0: 'a'. The permutation is indeed 'bca'.

Generalization

Equitext is trivially extended to any alphabet. The alphabet specific to the text (that is, the set of characters that the text uses) is extracted from the text thanks to a preliminary pass. It is then ordered using the Unicode code point of each of its characters. The length of chunks of text to be encoded to permutations is deduced from the size N of the alphabet. It's the greatest n such that N^n <= N!

The text might require to be padded in order for its length to be divisible by the length of a chunk. The text is padded by repeting the character of the alphabet whose ordinal indicates the length of the pad. The length of the pad can't be greater than the size of the alphabet because as a pad it has a lesser length than a chunk which itself has a lesser length than the size of the alphabet (otherwise N^n would be greater than N!), so we'll always have enough characters in the alphabet to encode the length of the pad using only one character.

Big Bang

2016-02-27T00:00:00Z

I've read Big Bang by Simon Singh. It's a big piece of literature, about 460 pages written in a tiny font, and I was quite impressed when it was given to me at Christmas, since I'm not a big book reader. However, it was so interesting that I had no trouble finishing it. The author does a wonderful job at telling the long story that leads to the Big Bang theory as it is today (as it was in 2004, actually, the year the book was released).

At some moments he doesn't hesitate to venture into the technical side of things yet he keeps it simple and accessible to anyone with basic middle school education. The way the story is written and its details suggest that the author has been studying a massive amount of documentation for the writing, and the bibliography at the end of the book is a proof of that.

Big Bang confirms my feeling that a historical depiction of how something was built is the best way to understand how it works. One of the first class that I took in my engineering school was about the working of a CPU. The professor based his course on how processors were built, historically. He started with the basic, early proof-of-concepts, and then explained how components were gradually added, and for what purpose. Of my three years of school, this was definitively the most interesting course. Such a chronological structure leads to a great understanding of the matter and also makes the overall course way more interesting than a raw description.

Carl Sagan explains how Eratosthenes deduced the circumference of the Earth. This is the kind of explanations and stories the book contains, this one in particular is given at the beginning of the book.

The book does the same thing with the Big Bang, this theory that I knew about but never managed to understand even superficially (I mean, other than "there was some sort of explosion and since then the Universe is expanding"). It explains why the idea emerged in the first place, what were the alternative theories, what observations favored the Big Bang theory rather than another one, etc. It's a novel and as such, it never forgets to draw up portraits of the scientists involved in the process, the concrete experiments that they were doing, as well as little anecdotes scattered here and there. I loved the little cliffhangers that the author leaves at the end of chapters, giving a hint on how someone is going to discover some amazing thing in the next chapter. This makes it look like a thriller.

When reading Big Bang I realized how science makes sense, and how people criticizing it in favor of alternative beliefs just lack knowledge. Things like the Big Bang (before reading the book) or quantum mechanics are so obscure for someone like me who only has a training on classical mechanics that the only way I would think them true is by having confidence in science. And while I always had 100% confidence in it (it works, bitches), there's no such thing as an understanding of why it's justified. And that's what this book brings. It brings an explanation of how much sense scientific theories make, how solid they are. The usage of the word theory doesn't mean that scientists have made an enigmatic bet that their hypothesis might somewhat be true. It means that even when observing how well their hypothesis works, they stay wise and careful in front of the peculiarities of Nature.

Nevertheless, the book gives a less idealistic vision of scientists that I imagined. I always pictured scientists as perfectly partial and unbiased people, and forgot that they were humans too. Big Bang shows how scientists can be seduced by a theory not only because of how faithful it is to reality but also because of its beauty or how it corresponds to their "intuition" of how Nature behave (or, worse, how it should behave). While the simplicity of a theory is really important, which, in a sense, makes the beauty matter not irrelevant, the book shows that some scientists are prone to kill the simplicity of a theory by applying patches to it to make it both compatible with observation and their personal beliefs of how it should work.

The best example is probably Ptolemy which added epicycles to the orbits of planets so that they could continue to orbit around the Earth and the epicycle thing would explain their visible retrogradations in the sky. Another shocking example is when the dynamic aspect of the Universe was a consequence of Einstein's general relativity, but Einstein liked a static Universe better, so he added some constant (the cosmological constant) in the equations to make it static. Friedman and Lemaître chose to really study the consequences of the original, patch-less theory, and ended up elaborating the first version of the Big Bang theory.

The great Richard Feynman explains how science works

The problem is that once you've made your point and defended it, it's hard to change your mind. The more you defend your theory, the harder it is to admit that you were wrong all this time. And it's really sad when someone seems to no longer base his or her opinion on the more recent data, but on the fact that they're just too deeply engaged to their view at this point. To a certain extend, the book gave me the impression that this phenomenon had a significant impact on the battle between the defenders of the Big Bang theory and the defenders of the Steady State theory. The latter was a new theory that emerged after the Big Bang theory and modeled a static universe instead of an expanding one. It was way more elaborated that the cosmological constant patch. At some point in History, it even explained observations that the Big Bang didn't.

At some point in the book, it feels like defenders of each theory are no longer defending their side because it best describes reality, but because they want to be right in front of the other side. Some of their arguments were no longer reasonable but different kinds of sophism instead. Actually, the kind-of-childish term "Big Bang" was first used by Fred Hoyle (defender of the Steady State theory) in order to make fool of the theory which involved some kind of big explosion. Defenders of the Big Bang though it was a nice term, so they adopted it. What takes the cake is that the same Hoyle was the co-author of a paper which explained how heavy elements are created inside stars*, which, at the time, was a better argument for the Big Bang than for the Steady State. The man definitely didn't know how to defend its theory properly, but fortunately that's for the good of knowledge.

*The whole team was: Margaret Burbidge, Geoffrey Burbidge, William Fowler, and Fred Hoyle. Hence the nickname of their monumental paper: B2FH

The only thing more badass than this picture is its caption on Wikipedia: The first six primary mirror segments being prepped for final cryogenic acceptance testing.

Finally, if there is one thing that I should remember from this book, it's that telescopes are the ultimate referees when it comes to know the Universe. It's like Feynman said in the video: you can develop the theory you want, to can marketize the theory as you want, you can think of all the arguments you want, you can wish and hope what you want. At the end of day, someone's going to build a telescope bigger than ever, and its observations will decide of the future of your theory without mercy.

I'm really looking forward to the launch of the James-Webb Space Telescope in 2018. Those things are knowledge fuel.

TL;DR: 10/10 would read again

The music I listen to

2016-01-18T00:00:00Z

When I switched to Linux last summer, the only software non compatible with Linux that I couldn't do without was foobar2000. I make it work using Wine. There are several reasons I consider this audio player and library manager to be superior to many others. To begin, its GUI is highly customizable via the so-called "Layout Editing Mode". There are a fair number of useful widgets that you can choose from and place on the screen, using a system of vertical and horizontal splits that you can add recursively.

Another good feature are the "Global Hotkeys", which make it possible to map keyboard shortcuts to various commands (pause, next song, change volume, switch the playlist order from random to default, etc), and these shortcuts work even if the player hasn't the focus. It's particularly useful when playing video games while listening to music.

Finally, plugins can be installed, some of which are powerful. My favorite is "Playback Statistics" which keeps track of the time a song has been added to the library, the first time and last time it has been played, and its play count.

Using this plugin, I like to compute my own little charts and see statistics about the music I listen to. However, exporting the data to a programmatically exploitable format wasn't as easy as I thought.

The ID mystery

Playback Statistics (PS) has a feature that allow one to "export data" (resp. "import data"). The intent of this feature is to make it possible to share statistics across different foobar2000 installations. The exported file is an XML file containing one node per song in the library with an attribute for each piece of data. Here's an example of a node corresponding to one song:

<Entry ID="eef3112353c1512d" Count="5" FirstPlayed="130818970132330604" LastPlayed="130913311506349590" Added="130739450382613924" />

The timestamps for the last three attributes are in the Microsoft FILETIME format. It's the number of 100-nanoseconds since January 1 1601. Don't ask me.

The problem is that the song is identified by an ID and nobody knows how it's computed from the song. The PS documentation implies that the ID is computed from the following song's metadata: artist, title, album, disc number, track number. However, from GitHub to Hydrogen Audio, nobody succeeded in guessing how the ID is computed from a song.

I tried to break the mysterious hash myself without success. I did two successive exports separated by a specific song's listening session. In the two XML files, I spotted the only element that had a PlayCount increment and deduced that it was the song I'd listened to. Note that the order of the songs aren't always the same, so I couldn't perform a simple diff and had to actually parse the XML to spot the difference. Having linked one song to its ID, I then tried to brute-force the ID. I tried all the combinations of the metadata said to be used in the documentation, with various separators between the fields, then encoded with various character encodings, then hashed with the most famous hash functions. At the heart of this 4 for-loops imbrication, I finally tested if the mysterious ID was a substring of the obtained hash. This resulted in zero match. I figured that the author could have used a more complicated hashing process. He could even have used a custom salt somewhere in the process. This was hopeless.

The next logical step was probably either to contact the plugin's author or to try to decompile the plugin's dll. But this is when I stumbled upon this Hydrogen Audio thread where a method to link each song of the library to its ID was exposed. This method relies on another plugin, "Text Tools". This plugin enables the user to export text information about the songs in the library, accessing the songs' metadata. Foobar2000 exposes metadata in the form of variables surrounded by the % symbol. For example, %title% gives the song's title. Fair enough, the PS plugin exposes its own variables (play count, first played, etc) using this format. For example, %play_count% gives the song's play count. Wonderful! Using only Text Tools I was then able to export all relevant information about the library!

The Music Diary

On the Figure 1 (you can right-click on it and click to "Show Image" to see the full-size version), each point represents a tracked song from my library. A tracked song is a song that I listened to at least one time since I've installed the Playback Statistics plugin. The plugin increments the play count of a song when the player plays at least one straight minute of it. This leads to misleadings numbers. For example, one of the track I've listened the most to is The Fourth Movement of Beethoven's Fifth Symphony, with a Play Count (PC) of 102. However, this track is about 10 minutes long and I know that I've mostly listened only to the last 3 minutes of it. (What an epic finale!)

Figure 1

The X-axis represents the first time I've listened to a song. The Y-axis represents the Play Count of the song as of the writing of this article. It's not a surprise that the left of the graph, starting a little before June 2013, is flooded with many songs. That's all the songs I was casually listening to suddenly starting being tracked by the plugin. However, you can obverse the same phenomenon one year later in June 2014, which contains a high concentration of new songs too. That's because I like to explore new music during the summer holidays. The effect lose strength in the summer of 2015, which I assume is because I was doing an internship and didn't have as much time as I had during previous summers.

An interesting phenomenon takes place between September 2013 and February 2014. As you can see, I haven't discovered many songs in this period. However, the few I did I listened to them a lot of times! Well, this period was when I moved outside my parents' to study in a new city and I didn't have an Internet connexion in my new apartment. I remember exploring a bit of music at my school's computers and listening to them a lot in my apartment as I didn't have much to do.

I have a few ultra popular songs that I listen to massively. Breaking Through by Audiomachine holds the record with a stratospheric 153 PC. Songs with the highest PC tends to be older, having been listened for the first time around 2013. This makes sense, since the older a song is, the more time I have to listen to it repetitively and increment its PC. My favorite songs that I discovered recently are Take me To Church by Hozier and Take a Look Around by Limp Bizkit. The former is recent and I discovered it when it became popular worldwide. The latter dates back from 2000 and I just became fond of it when I discovered it last summer. I played it in loop while playing Urban Terror, which certainly contributed to its high PC.

You can see vertical ribs, for example at the beginning of last December or at the beginning of March 2015. That's when I discover an album. I listen to the whole album in one go. Then I listen to each track individually according to my preferences. Each track then evolves on the album's vertical line.

Finally, you can see how serious I am each year before my finals, during a little period around the end of April and the beginning of May, where I don't listen to any new song, except for Audiomachine's Millennium in May 2015. Indeed, I remember discovering it at the end of this movies montage during a procrastinating session.

The Fluff Principle

The Fluff Principle is a term invented by Paul Graham in a February 2009 article. The Hacker News creator gives the following definition:

on a user-voted news site, the links that are easiest to judge will take over unless you take specific measures to prevent it.

He explains that one type of fluff is short content. It's faster to consume a joke or a picture than an in-depth article. Therefore, at equal quality, the former will gain more upvotes per unit of time than the latter.

Well, the Fluff Principle also holds for my music statistics. It's faster to listen to a short song than to a long one. Therefore, at equal quality, short songs will gain more PC by unit of time than long ones. For example, my top one song, Audiomachine's Breaking Through (153 PC), is only 1:18 long. I know that I've listened to another song, Seven Angels by Avantasia a crazy amount of time, each time the whole thing. However, this song is 14:17, so it's not quite a surprise that its PC is only 31. Now if I want to know how much time I've been listening to each song, that is, the total amount of time I was listening while the song was playing, I have to multiple the PC by the song's duration. Breaking Through hits 153×(1×60+18) = 11,934 seconds. Seven Angels hits 37×(14×60+17) = 31,709 seconds. Wow! I've listened to Seven Angels way more than to Breaking Through!

Following this observation, we can define the Normalized Play Count (NPC) as the following: NPC(song) = PC(song)×Duration(song)/AD where AD is the Average Duration of a tracked song. This way, for songs which have a duration close to the average duration, their NPC will be approximately equal to their PC. The NPC plays an important role for particularly short songs, for which it diminishes their importance, and for long songs, for which it increases the importance.

The table on Figure 2 shows the top 20 songs in my library sorted by their NPC, in the reverse order. This table contains several anomalies that are due to the fact that the PS plugin increments the PC of a song only when 1 minute of it is played. Anomalies are very long tracks whose duration tends to give them a high NPC when in reality I listened only to a part of them. The anomalies are:

Ranked 1: It's 20 minutes long, but I know I almost never listen beyond the 10 minutes mark.
Ranked 2: It's 10 minutes long, but I almost always listen to its finale, that is the last 3-4 minutes.
Ranked 6: Final song of the album. I usually only listen to the first 3-4 minutes.
Ranked 9: I never listen to the Quasimodo Suite, which is quite lengthy.

Rank	Artist	Title	NPC
1	Beethoven	Piano Concerto No.5: Mvt. I	384.107
2	Beethoven	Symphony No.5 - IV Allegro	320.7867
3	Dvorak	Symphony No. 9: II. Largo	143.867
4	Avantasia	The Seven Angels	109.836
5	M83	Raconte-Moi Une Histoire	97.736
6	Awolnation	Knights of Shame	96.200
7	Audiomachine	Rising Dawn	95.217
8	Zack Hemsey	Vengeance	90.881
9	Santa Esmeralda	The House of the Rising Sun + Quasimodo Suite	85.195
10	Limp Bizkit	Take a Look Around	83.250
11	Mahler	Symphony No. 1 - Mvt. IV	81.503
12	Beethoven	Symphony No.5 - II Adante con moto	80.673
13	Macklemore & Ryan Lewis	Wing$	80.525
14	Hozier	Take Me to Church	79.947
15	Hans Zimmer	Mombasa	78.914
16	Edwyn Collins	A Girl Like You	78.295
17	Beethoven	Moonlight Sonata - Third Movement	78.282
18	Beethoven	Piano Concerto No.5: Mvt. II	75.685
19	M83	Wait	73.653
20	Beethoven	Piano Concerto No.5: Mvt. III	72.167

Figure 2

The np problem, Reddit edition

2015-12-05T00:00:00Z

Have you ever been redirected to a so-called read-only version of Reddit? That's a thing. For example, check out np.reddit.com/r/books. No voting arrows, no button to comment even when logged in, and a little message at the top of the subreddit: "You have been linked to a read-only version of this subreddit. Please respect the community by not voting." All because the little np ("No Participation") subdomain was used. Now if you try the same thing with /r/askreddit: np.reddit.com/r/askreddit, everything is absolutely normal, no difference with the regular Reddit. Quite strange, isn't it. It doesn't stop there. For example, sf.reddit.com/r/teenagers displays only the self-post of the subreddit, because of the sf (SelF-posts) subdomain. But that only works for /r/teenagers. So, what the well?

How Reddit subdomains work

One good thing about reddit is that it's open-source. So one can inspect the code related to subdomains handling to understand how it works. I did read the code, and this is what I discovered.

Reddit accepts subdomains that indicates the language with which the site should be displayed. What's interesting is that Reddit doesn't have a predefined list of strings that are accepted as a language subdomain, but uses a regular expression instead: \A\w\w(-\w\w)?\Z. So, basically, any sequence of two alphanumerical characters, optionally followed by a dash and another such sequence is accepted. For example, zz or an-42 are valid language subdomains, even though they correspond to no language code in the ISO 639-1 specification.

What does Reddit do with such code? Well, for some real languages such as French (fr) or Japanese (ja), the web interface is actually translated into the language. For the more esoteric codes that I invented in the paragraph above, it does nothing to the interface. However, for any given code, it performs one thing: in the HTML of the web page, it sets the value of the lang attribute of the html root tag to the code provided. So, when you browse to an-42.reddit.com, the HTML source of the page starts with:

<!doctype html><html xmlns="http://www.w3.org/1999/xhtml" lang="an-42" xml:lang="an-42">

Using and abusing CSS

On Reddit, despite doing the hard and benevolent work of maintaining subreddits, moderators have only access to quite rudimentary tools. Actually the improvement of moderator tools is always brought to the table when the admins risk themselves into asking the community for feedback. This issue was critical when last summer reddit let go the employee in charge of the relations between the moderators of /r/IamA and the celebrities doing interviews, all without warning the moderators, generating a massive reddit-wide drama.

Anyway, it's a matter of fact that there are no moderator tools to customize the user experience depending on the subdomain used, nor tools to add custom modules or text areas anywhere in the subreddit page. However, the moderators have access to one thing: they can edit the CSS stylesheet used to render the subreddit. And that's the key to everything. CSS is like editing in film-making; no matter what material you have, you can transform it into whatever you want. CSS is power.

The basic idea is that if you prefix some CSS rules with the body:lang(np) selector, the rule will only apply to pages whose html tag have their lang attribute set to np. So, as a Reddit moderator, you can effectively define rules for specific subdomains. You can then use the power of CSS to fully customize the page for this subdomain. You can, especially, make things disappear using the display: none property:

body:lang(np) .usertext-edit,
body:lang(np) .sidebox.submit,
body:lang(np) .commentingAs,
body:lang(np) .markdownEditor, 
body:lang(np) a[onclick*="return reply(this)"],
body:lang(np) .helplink
{
    display: none !important;
}

Additionally, you can make new things appear using the content CSS property coupled with the :before or :after selector:

body:lang(np) #siteTable:before
{
    content: "You have been linked to a read-only version of this subreddit. Please respect the community by not voting.";
    display: block;
    max-width: 800px;
    background-color: #F6E69F;
    padding: 5px 10px;
    margin: 5px 305px 5px 0px;
    border: 1px solid orange;
    font-size: small;
}

A drawback of adding content using this method is that the inserted text is not selectable. This can be frustrating from a user-experience point of view.

The code snippets provided above come from the actual stylesheet provided by the /r/NoParticipation subreddit, which is dedicated to instruct moderators on how to "install" the "No Participation mode" on their own subreddits. In the next part, I explain how such a subreddit was born and why moderators would want to add a "No Participation mode" to their subreddit.

Combating cross-subreddit contamination with the No Participation mode

There are such things known as the meta subreddits. On such subreddits, users share links and comment about what happen on Reddit. For example, /r/BestOf is for comments which are awesome in some way and which constitutes the "best of" Reddit. /r/ThreadKillers is for comments which answer a question or a request in such a comprehensive way that any additional comment from other users is not necessary. /r/DepthHub is for comments which answer a question in depth. /r/SubredditDrama is for following flame-wars going on Reddit.

The subreddits these meta-subreddits link to sometimes are little subreddits or even niche subreddits, for example dedicated to specific hobbies. The problem is that meta-subreddits' users, instead of just being spectators of what's happening on Reddit, would sometimes go on and enter the show, voting on comments of the thread linked, posting comments themselves and so on. On top of disrupting the normal flow of upvotes and downvotes and disrespect the explicit and implicit submission guidelines of the subreddits they were showing up in, users would sometimes perform vote brigading, that is, massively downvoting a opinion they disagree with so that it would be buried in the abyss of the comments and become invisible.

To combat this problem, redditor /u/KortoloB had an idea. He figured out the technical elements explained in the previous part and wrote a "no participation" stylesheet dedicated to the np subdomain. This is the stylesheet which contain the snippets presented in the previous part. He created the subreddit /r/NoParticipation to host and support his idea. He abstracted the technical working of the stylesheet into what he calls the No Participation mode and wrote instruction on how to install the No Participation mode on one's subreddit (basically instructing to copy and paste the stylesheet).

To make /u/KortoloB's idea work reddit-wide, there were two additional conditions: that regular subreddits install the No Participation Mode, and that the meta subreddits' submissions point to the No Participation mode of other subreddits. I don't know the exact time-line of events, but as of today, the NP mode is deployed on a lot of subreddits and the system works pretty well. This page lists all the subreddits that have No Participation installed, as well as meta-subreddits that instruct users to only post links pointing to the NP version of a subreddit, some of them requiring it (i.e. removing posts that don't respect the rule).

Reaction of the community and of the reddit staff

My impression as a regular redditor is that the No Participation thing caused and is still causing a lot of confusion in the Reddit community.

Most redditors know that moderators tools a quite limited and seeing voting arrows disappearing depending on the subdomain in the URL gives them the impression that the No Participation mode must be some kind of official Reddit feature. Furthermore, to even more discourage users to participate in the No Participation mode, some moderators launched the rumor that removing the np subdomain and reloading the page to participate would result in them being banned. However, moderators have no way to detect such behavior and admins have nothing to do with the No Participation mode. Technically, you don't even have to reload the page to participate, but just to disable the styles defined by the moderators. Since Reddit delivers the moderator stylesheet as a separate CSS file upon a client request, it's fairly easy with any browser's development tools to disable only the moderators styles.

When confused users would ask in several threads what the hell the No Participation mode was, some would answer by only giving a few bullet points about what this mode changed, in a tone that would validate the false idea that it's an official reddit feature. Some other would accurately explain that it's nothing more than a hack from the moderators that exploit the np language subdomain. Some would let think that moderators have a direct tool to customize a subreddit depending on the language, not clarifying that elements of the page are still there but just hidden. Fortunately, some other would accurately explain that it's a CSS hack.

A rumor that became popular is that the np language subdomain is for the Nepalese version of Reddit. In fact, the Nepalese language code is ne, not np (the location code of Nepal is NP, but Reddit's subdomain are not made for locations code). Furthermore, as explained in the first part of this article, Reddit accept any combination of two letters as the language subdomain. np corresponds to no language according to the ISO standard.

In the 2014 thread about the Reddit official blogpost How reddit works, when a user asked about the No Participation mode, the admin /u/cupcake1713 clarified that it wasn't actually something from the Reddit staff and called it a "crappy CSS hack" (and stroke the "crappy" out later, probably by remorse after No Participation creator answered to her comment and said being a little bit affected that his idea was denigrated so much by the admins). She also pointed out that the admins realized quite recently (relatively to the date of her comment) that the NP stylesheet was hiding the "report" button on submissions (a button to report abuse), that this was a "huge problem" and that if the staff would have spotted this problem sooner they would have stop the spread of this thing. The no participation stylesheet is since fixed and doesn't hide the report button.

Since then, other subreddits have customized other subdomains for other purposes (cf. sf on /r/teenagers for showing only self-posts). Last summer, admins said that they'll deploy better moderation tools by 2016. My bet is that it won't include any non-participation related stuff. It's too easy to override and it probably wouldn't scale well. I just want moderators to be able to add custom text boxes in the page without CSS so that the text is selectable. There's something deeply wrong with non-selectable text.

Datetime in Python

2015-11-26T00:00:00Z

Last Friday I spent two hours fighting with the datetime class from Python's datetime module. I originally thought that a datetime object represented a single point in time, which is not always the case. I sum up with a few bullets points what I learned about this module:

In its simplest form, a datetime object is just a date and a time as you would write it down on a piece of paper. It's a year, a month, a day, and, optionally, an hour, a minute, a second and some microseconds (the 'time' part of 'datetime').
So, in this simplest form, a datetime object does not represent a given point in time because it depends on the timezone in which you consider your date and time. It's up to interpretation. Such datetime objects are called naive. You can make a datetime object aware by giving to it the timezone that should be used to interpret this date and time. An aware datetime object does represent a given point in time.
The optionnal timezone carried by a datetime object is given by the tzinfo attribute, whose value is of type tzinfo. The tzinfo class is an abstract base class, meaning you can't directly instanciate a tzinfo object. You must instanciate a subclass of tzinfo, such as timezone. But to construct a timezone object, you must give it a timedelta object. The timedelta class represents a difference between two datetimes. When used to construct a timezone, it indicates the offset in relation to UTC. For example, timezone(timedelta(hours=2)) is a valid tzinfo object which represents the timezone UTC+2. timezone.utc is a shortcut for timezone(timedelta(0)).
Most methods which return a datetime object return a naive object. The method now returns the local and naive date and time; the method utcnow returns the UTC naive date and time. Since Python 3.2, the strptime method can produce an aware datetime object from a string. The string must contain the timezone in the +HHMM or -HHMM format (for example +0200 for UTC+2), and the placeholder to use is %z to capture the timezone part.

Practical example

Let's say you've acquired such a string representating a date and a time: Mon Nov 23 20:06:13 CET 2015. It's actually the default output's format of the date command in bash. Let's say you want to write a Python script that tells you the exact time difference between the moment the script is executed and the date and time represented by this string.

We're in bad luck here because Python won't be able to tell us to what timezone CET corresponds to. Remember, it can only parse timezones if they're in the form +HHMM. So we need to do some basic research. It turns out that CET stands for Central European Time and is UTC+1.

Now that we have such knowledge, a solution is to replace CET by +0100 in the string then let Python produces an aware datetime object.

from datetime import datetime, timedelta, timezone

DATETIME_STRING = 'Mon Nov 23 20:06:13 CET 2015'
string = DATETIME_STRING.replace('CET', '+0100')
dt = datetime.strptime(string, '%a %b %d %H:%M:%S %z %Y')

Now, we need the current time. There are two functions to get the current time: now or utcnow. The problem with now is that it returns the current local time. So we would need to figure out what is the local timezone, which isn't straightforward (more on that later). utcnow returns the UTC time, so we know the timezone by definition. Note that even if we know the timezone, utcnow still returns a naive object, so we'll have to manually set the timezone to UTC:

now = datetime.utcnow()
now = now.replace(tzinfo=timezone.utc) # Getting an aware datetime object

We can now subtract the two datetime objects to obtain a timedelta object, which has the fancy seconds attribute:

delta = now - dt
print(delta.seconds) # Prints the timespan in seconds between dt and now

Getting the local timezone

In the last part, another strategy would have been to use the now to obtain the local time and then set the local timezone to the datetime object obtained. But getting the local timezone isn't easy. I haven't found any function in the documentation doing that, and posts on the subject on StackOverflow advice using the tzlocal module, which isn't present in the standard library.

It's still possible with the vanilla datetime module.

First, a solution that would work sometimes:

diff = datetime.now() - datetime.utcnow()
minutes = round(diff.seconds / 60)
local_timezone = timezone(timedelta(minutes=minutes))

Here we get the timezone as the difference between now and utcnow. But since the two functions are not executed at the exact same time, the difference doesn't produce a timedelta object with a whole number of minutes, which is the condition for a timedelta to be used to construct a timezone. We get a whole number of minutes by rounding the number of seconds divided by 60. Then we construct a timezone thanks to a new timedelta.

Now imagine that this code runs on a very slow computer and more than a minute is gone between the execution of the two functions, and you've got a corrupted timezone. So, it doesn't really work.

To make it work we can use a timestamp. Python can parse POSIX timestamp into datetime objects. We can use fromtimestamp to get the local datetime from a timestamp and utcfromtimestamp to get the UTC datetime from the same timestamp, then substract the two, which, this time, will represent the exact same instant:

TIMESTAMP = 42
dt_utc = datetime.utcfromtimestamp(TIMESTAMP)
dt_local = datetime.fromtimestamp(TIMESTAMP)
diff = dt_local - dt_utc
local_timezone = timezone(diff)

Well, to be perfectly honnest, I'm still not absolutely convinced that this would work 100% of the time. Depending on the implementation of the fromtimestamps methods, there may exist edge cases causing trouble some times. I don't know. At the end of the day, the true way to get the timezone is to look at the operating system's specific configuration file containing such information, which is set by the user when it installs the operating system. This is what the tzlocal module does by the way. Python probably does it too when it does anything UTC.

Why Firefox was losing track of my history

2015-07-01T00:00:00Z

A few months ago I encrypted my Firefox profile. It contains my history, bookmarks and most importantly, authentification cookies that I keep for websites I find more conveniant to stay logged in. Those are things I prefer to be encrypted for obvious privacy and security reasons.

The process of encrypting a Firefox profile goes as follow: first, you need to know where the profile is located in the disk. On Windows, it's a directory which sits at {User direcory}\AppData\Roaming\Mozilla\Firefox\Profiles\{the profile directory}. Then you need to use an encryption software such as TrueCrypt to put this directory in an encrypted container. Once you have this container, this is how a software like TrueCrypt works: when you open a container with it, it'll query you with the password and if you enter the correct one it'll mount the container as if it was an external storage device. On Windows, this makes a new disk appear (you know like C: or D: or whatever) and all the content of the container becomes available at this disk. TrueCrypt lets you choose the letter of the disk on which you want to mount the container.

In this case, the content of the container is a Firefox profile, so you have to tell Firefox how to access it once it's mounted. This can be done using the Firefox profile manager. In fact Firefox let's you create an arbitrary number of profiles. A profile has a name, and a path indicating where the actual profile directory is on the computer. Here, the strategy is to choose a letter by convention, which will be the letter of the drive onto which we're always going to mount the Firefox profile container. For example, we can take R:\ (I prefer letters at the end of the alphabets because Windows uses letters at the begining at the alphabet to automatically mount external devices). So we're gonna create a Firefox profile and set its path to R:\

When all this set up is ready, when you want to browse Firefox, first you mount the profile container to R:\ and then you open Firefox with the corresponding profile. When you finish browsing, you close Firefox and you dismount the container. That is a dull process, so you can, like me, write some little batch script that'll make it almost transparent: it just asks me the password when I click on the Firefox icon and does the job of mounting before opening Firefox and dismounting when I close Firefox.

This was not intented to be a tutorial on how to encrypt a Firefox profile, but just an introduction to the rest of this article. This is a step-by-step guide on how to encrypt a Firefox profile.

When you create a container, you need to indicate the size of the container. Before encryption, my profile weighted around 230 MB, so I figured that 500 MB was enough for the container. Well, in fact, Firefox had a little surprise for me.

A few weeks after I had set up my encrypted profile, I noticed that Firefox was losing old history. I never delete my history. It goes (went) all the way to more than six months, actually all the way to when I started my computer for the first time. I was first alerted by auto-completion fails. Having a massive history lets Firefox performs some very helpful and comprehensive auto-completion magic in the address bar; but this time it wasn't even able to auto-complete "reddit.com/r/askr". What the hell was going on. Then I discovered in the Library window that there was nothing more than "This month". I was mad. My data had disappeared.

After some googling I found out why.

It turns out that by default, Firefox delete old history based on some expiration criterias. This is the source code of the program doing this slanderous job.

Look at this:

// This percentage of disk size is used to protect against calculating a too
// large database size on disks with tiny quota or available space.
const DATABASE_TO_DISK_PERC = 2;

If there is not much space available on the disk, the history database can't take up more than 2% of this available space. My container has a size of 500 MB, but about 230 MB are already taken by other stuff (bookmarks, thumbnails, extensions, etc), so there's 270 MB actually available. So, the maximum size of the database was 5.4 MB. That's not much.

Then there's this:

// This is the average size in bytes of an URI entry in the database.
// Magic numbers are determined through analysis of the distribution of a ratio
// between number of unique URIs and database size among our users.
// Based on these values we evaluate how many unique URIs we can handle before
// starting expiring some.
const URIENTRY_AVG_SIZE = 1600;

Firefox computes the maximum number of URIs it can hold in the database thanks to an average URI size, whose value is set to 1.6 KB. With 5.4 MB available, it means that you can store up to 3375 URIs. I don't know about you, but for me, that's about 15 days of browsing the web.

So, this is why my history was only available for 2 weeks.

The solution to this problem was quite easy. Actually all this hardware calculation for the maximum number of URIs is used only if the maximum size isn't set by the user. There's no regular settings menu to set this preference, I had to go in about:config. According to this, there should be 2 keys relative to the limit of URIs: places.history.expiration.max_pages which can be set by the user to his convenience and places.history.expiration.transient_current_max_pages, a read-only copy of the previous key destined to other components which would want to access this information. When I finally searched for the keys, only the read-only one was there (and its value was 3274, close but not equal to my estimation above, that's because I rounded the numbers). According to this forum post, I simply could create a brand new key called places.history.expiration.max_pages and do my business with it. Which I did, setting its value to one fucking million. I was glad to see that its twin key immediatly updated itself with the new value, indicating that it worked.