Two centuries on, scientists are still searching for a proof of its universal validity By In real life, laws are broken all the time. Besides your everyday criminals, there are scammers and fraudsters, politicians and mobsters, corporations and nations that regard laws as suggestions rather than restrictions. It’s not that way in physics.
For centuries, physicists have been identifying laws of nature that are invariably unbreakable. Those laws govern matter, motion, electricity and gravity, and nearly every other known physical process. Nature’s laws are at the root of everything from the weather to nuclear weaponry.
Most of those laws are pretty well understood, at least by the experts who study and use them. But one remains mysterious. It is widely cited as inviolable and acclaimed as applicable to everything.
It guides the functioning of machines, life and the universe as a whole. Yet scientists cannot settle on one clear way of expressing it, and its underlying foundation has evaded explanation — attempts to prove it rigorously have failed. It’s known as the second law of thermodynamics.
Or quite commonly, just the Second Law. In common (oversimplified) terms, the Second Law asserts that heat flows from hot to cold. Or that doing work always produces waste heat.
Or that order succumbs to disorder. Its technical definition has been more difficult to phrase, despite many attempts. As 20th century physicist Percy Bridgman once wrote, “There have been nearly as many.