4 ms·
The demon is introduced as a magical effect, but the obvious followup question is why can't you actually implement it. Why can't you make a machine that lowers
by Strilanc 5y ago
The demon is introduced as a magical effect, but the obvious followup question is why can't you actually implement it. Why can't you make a machine that lowers entropy by opening and closing a door to let atoms go one way but not the other? Why can't you make a one-way valve? What specifically is magical about the demon? There is an important insight hiding inside that demon.
- jakobnissen 5y agoThe demon is not really supposed to be magical, but instead "some physical process or machine", e.g. a future nanomachine or something. It's like a "perpetual motion machine" - a hypothetical object that can be used in thought experiments. If it could be shown that creating a Maxwell's demon that creates less entropy than it reduces is impossible, then the paradox is solved. A [brownian ratchet](https://en.wikipedia.org/wiki/Brownian_ratchet https://en.wikipedia.org/wiki/Brownian_ratchet) is an example of a (failed) implementation.
- ctdonath 5y agoWhat’s magical: it can observe, decide, and act with zero energy (or at least less energy than real-world thermodynamics requires).
- chriswarbo 5y ago> observe This isn't magical: it's just entanglement/causality. If "observing" required energy, then atoms would either blow apart (due to their electrons not "observing" their nuclei), or collapse (due to their electrons losing energy by "observing" their nuclei). > decide This isn't magical: https://en.wikipedia.org/wiki/Billiard-ball_computer https://en.wikipedia.org/wiki/Billiard-ball_computer > act This isn't magical: https://en.wikipedia.org/wiki/Conservative_force https://en.wikipedia.org/wiki/Conservative_force