Ciro Santilli @cirosantilli 37

Theory that atoms exist, i.e. matter is not continuous.

Much before atoms were thought to be "experimentally real", chemists from the 19th century already used "conceptual atoms" as units for the proportions observed in macroscopic chemical reactions, e.g. $2H_2+O_2\leftrightarrow H_{2}O$. The thing is, there was still the possibility that those proportions were made up of something continuous that for some reason could only combine in the given proportions, so the atoms could only be strictly consider calculatory devices pending further evidence.

Subtle is the Lord by Abraham Pais (1982) chapter 5 "The reality of molecules" has some good mentions. Notably, physicists generally came to believe in atoms earlier than chemists, because the phenomena they were most interested in, e.g. pressure in the ideal gas law, and then Maxwell-Boltzmann statistics just scream atoms more loudly than chemical reactions, as they saw that these phenomena could be explained to some degree by traditional mechanics of little balls.

Confusion around the probabilistic nature of the second law of thermodynamics was also used as a physical counterargument by some. Pais mentions that Wilhelm Ostwald notably argued that the time reversibility of classical mechanics + the second law being a fundamental law of physics (and not just probabilistic, which is the correct hypothesis as we now understand) must imply that atoms are not classic billiard balls, otherwise the second law could be broken.

Pais also mentions that a big "chemical" breakthrough was isomers suggest that atoms exist.

Very direct evidence evidence:

Less direct evidence:

Subtle is the Lord by Abraham Pais (1982) page 40 mentions several methods that Einstein used to "prove" that atoms were real. Perhaps the greatest argument of all is that several unrelated methods give the same estimates of atom size/mass:

Gwern Branwen's website.

One thing that annoys Ciro Santilli about that website are the footnote overload. Ciro likes linear things.

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A Hermitian matrix.

composite particle made up of an even number of elementary particles, most commonly one particle and one anti-particle.

This can be contrasted with mesons, which have an odd number of elementary particles, as mentioned at baryon vs meson vs lepton.

This is an interesting licensing model that might just scale.

One of the most powerful chess engine as of 2023: computer chess competition.

CLI program implementing Universal Chess Interface: www.reddit.com/r/ComputerChess/comments/b6rdez/commandline_options_for_stockfish/

How to actually play against it: chess.stackexchange.com/questions/4353/how-to-install-stockfish-on-ubuntu So hard!

A Turing machine decider is a program that decides if one or more Turing machines halts of not.

Of course, because what we know about the halting problem, there cannot exist a single decider that decides all Turing machines.

E.g. The Busy Beaver Challenge has a set of deciders clearly published, which decide a large part of BB(5). Their proposed deciders are listed at: discuss.bbchallenge.org/c/deciders/5 and actually applied ones at: bbchallenge.org.

But there are deciders that can decide large classes of turing machines.

Many (all/most?) deciders are based on simulation of machines with arbitrary cutoff hyperparameters, e.g. the cutoff space/time of a Turing machine cycler decider.

The simplest and most obvious example is the Turing machine cycler decider

I caught and overcame a minor addiction to Cataclysm: Dark Days Ahead.

It does bring back the The Sims feeling from my teenage years, but with killer zombies added in.

I especially like going to sleep in that game, and how you need to setup a confy bed for it.

Some further comments at: Section "Cataclysm: Dark Days Ahead".

The way to quit is simple: delete your saves, then get annoyed with slowness of progressing back up, then use built-in debug/cheat menu to overcome that, then it's not fun anymore. This is a major advantage of single player open source games: addiction resistance!

Added font awesome icons. github.com/ourbigbook/ourbigbook/issues/151

Didn't manage to subset, but so be it for now: stackoverflow.com/questions/62395038/how-can-i-export-only-one-character-from-ttf-woff-file-to-avoid-load-unnecessa/71197892#71197892

TODO understand.

After something broke on the website due to SQLite vs PostgreSQL inconsistencies and took me a day to figure it out, I finally decided to update the test system so that OURBIGBOOK_POSTGRES=true npm test will run the tests on PostgreSQL.

Originally, these were being run only on SQLite, which is the major use case for OurBigBook CLI, which came before the website.

But the website runs on PostgreSQL, so it is fundamental to test things in PostgreSQL as well.