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

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