The title entity controls a gate between two gas chambers and is able to cause a temperature difference, thus causing a decrease in entropy.
Henry Adams compared militant Germany to this thought experiment. Leó Szilárd noted that it has to have some way of acquiring and storing information, thereby refuting its formulator's claims. The Brownian ratchet is similar to this thought experiment, but Richard Feynman proved that it cannot actually produce useful work because the mechanism will not work under the theorized conditions. The title entity controls a gate between two gas chambers and is able to cause a temperature difference, thus causing a decrease in entropy. For 10 points, name this thought experiment formulated by a Scottish physicist, which seems to defy the second law of thermodynamics.
Henry Adams compared militant Germany to this thought experiment.
Maxwell's demon