What two theories contradict the second law of thermodynamics?

Answer 1

Like all physical laws, the second law applies with a few restrictions. If you ignore those restrictions, you can come up with apparent violations. But you're misapplying the law, not contradicting it.

Some people say the theory of evolution contradicts the second law because it posits an increase in order over time. That's silly for three reasons-

1. Evolution theory does not posit an increase in order- it isn't necessarily true that more complex forms evolve from less complex ones.
2. Entropy has everything to do with probability, and not much to do with "order" per se.
3. Even if 1 and 2 weren't true, you have to consider both the system and the surroundings in applying the second law. For example, making a baby from raw materials would seem to be a tremendous decrease in entropy, so babies might "violate" the second law. But consider the baby's effect on the universe around it, too- the surroundings experience an even greater increase in entropy during baby-making (food is broken down and wastes are produced) and the net entropy change for the universe is positive.

Answer 2

1. Maxwell's demon: The thought experiment suggests a way to violate the second law by using an intelligent being to selectively allow particles to pass through a barrier in a way that would decrease entropy.

2. Perpetual motion machines of the second kind: These machines aim to continuously produce work without any input, which would violate the second law by creating a perpetual motion system where entropy does not increase over time.