|
|
|
|
|
|
by mnl
2090 days ago
|
|
|
Being omniscient this special molecule can tell which identical molecule is which in the gas, that's some interesting physics. Of course it can also predict the final states of collisions between other molecules. Even when that information just doesn't exist in the perfect a priori knowledge about the system, which is something that if this special molecule could obtain somehow and then store for later use should violate half a dozen theorems or so. Really this could make some sense if we were talking about an ideal gas of classical particles that obey deterministic mechanics, but then not even the special molecule would be able to determine the initial conditions with sufficient precision to make useful predictions, beyond a short path and a few collisions in the system. |
|
|
Obviously the special molecule is a thought experiment to illustrate an idea under certain simplifying assumptions and extreme parameters, to understand the consequences. Nobody expects to make one.
And you are doing a proper job of arguing why it cannot work, as you are supposed to with a thought experiment.
But... it's not correct to reason that "it can't predict" when the "information just doesn't exist [...] a priori".
If the special molecule senses, computes and reacts entirely in the quantum realm itself, then its processing will be entangled with those other molecules.
Despite the absence of a priori final states, the special molecule is, in principle, able to select an entangled reaction to those final states anyway.
It's a bit like saying "I don't know if particle X will move to A or B later (and particle X hasn't decided either), but I can prepare myself into a state where if X moves to A then I will already be at A', and if X moves to B then I will already be at B'".
And if being at A' when X moves to A, or B' when X moves to B, means that X can't actually move to A or B, that entangled reaction will affect X so the question of A or B doesn't even arise in the first place.