Looking at the Second Law of Thermodynamics Through the Eyes of Maxwell’s Demon

Abstract

As we may gather from the above quotation, the Second Law of Thermodynamics maintains a privileged status for the professional scientist being the key to the explanation of most physical events. On the one hand it stands as a postulate for an extremely efficient theory such as Phenomenological Thermodynamics, on the other it holds a place of honor within the realm of physical laws because of its uniqueness; no other law expresses “impossibility” or an upper limit, or rather, all which do are in some way related to it.

The law that entropy always increases — the Second Law of thermodynamics — holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations- then so much worse for Maxwell’s equations. If it is found to be contradicted by observation, well, these experimentalists do bungle things sometimes. But if your theory is found to be against the Second Law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.

—A.S. Eddington