[JD557]

Unrelated to the word "daemon", but related to the article, I was a bit surprised by this assertion:

> Eventually, though, the theory of quantum mechanics showed why it wouldn't work.

I was familiar with the information theory arguments (the same presented in Wikipedia[1]). Is that why they mean here by "quantum mechanics" or is there another counterargument to Maxwell's daemon?

1: https://en.m.wikipedia.org/wiki/Maxwell's_demon#Criticism_an...

[n4r9]

I'm guessing that the daemon's ability to allow only fast molecules through the gate depends on knowing their position and velocity simultaneously?

[roywiggins]

It seems to come from measuring the particles at all. One result is that the demon has to store information about the particles, and erasing that information to free up memory increases the entropy of the gas/demon system.

https://en.m.wikipedia.org/wiki/Maxwell%27s_demon#Criticism_...

[BlueTemplar]

Yes, exactly, and this is what allows quantification.

http://www.av8n.com/physics/thermo/entropy-more.html#sec-pha...

With 'entropy' being an obsolete term for (lack of) information, and

> “classical thermodynamics” is a contradiction in terms.

[eru]

But the daemon doesn't need to know them all that precisely.

[Vecr]

It probably (if the calculations are right) is unable to actually do much of anything useful (because it's too complex to avoid being extremely correlated with the rest of the universe ("embedded")), and even if it could it wouldn't be better than a standard ASI in most real-world situations.

That's assuming you aren't trying to claw back more energy than you lose, I'm pretty sure that's not possible to reliably do without crazy hypothetical physics.