Don S. Lemons

“Loschmidt’s paradox Yet if, as is widely assumed, a thermodynamic system is composed of many fundamental particles and a thermodynamic process is composed of many fundamental interactions, why are not all thermodynamic processes reversible? Johann Loschmidt (1821–1895) asked this question in 1876. We still have no fully satisfactory answer. That many reversible fundamental processes do not necessarily compose a reversible thermodynamic process is known as Loschmidt’s paradox or the reversibility paradox. Our failure to resolve Loschmidt’s paradox suggests that the laws governing the interactions of fundamental particles do not form a complete picture of nature and need to be supplemented with additional physics equivalent to the second law of thermodynamics.”
― Don S. Lemons, A Student's Guide to Entropy

“Clausius derived the word entropy from the Greek root tropy meaning “turn” and a prefix en meaning in. Thus entropy literally means “in turn” or “turn in.”
― Don S. Lemons, A Student's Guide to Entropy