Hi Folks, (Skip to next paragraph if you already know what M's D is.) Maxwell's demon was a counterargument to the second law of thermodynamics (and hence the first) involving two chambers of air connected by a trap door which this demon would open and close to let fast molecules go one way and slow ones the other. One chamber gets hotter and can perpetually drive a heat engine. The catch apparently lies in the assumption that the demon himself can be neglected but in reality one has to consider the entropy associated with his decision. But this argument makes no reference to the size of the air molecules. What if they were whopping great cannonballs? Can one still claim that the energetic equivalent of whatever bits he has to erase in his head is comparable with the power station you could drive that way? How do we even make the comparison between energy and entropy here? Now that I think about it, I don't really understand why it would have been a problem in the first place. If I milk kinetic energy out of either chamber, all the cannonballs are gonna slow down eventually. But they did teach me in school that breaking the second law was tantamount to breaking the first. Confused, Adrian.