Image via Wikipedia
“Entropy is a thermodynamic quantity whose value depends on the physical state or condition of a system. It is useful in physics as a means of expressing the Second Law of Thermodynamics. That is, while the law may be stated in terms of it being impossible to extract heat from a reservoir and convert it totally to usable work, in terms of entropy the law states that any changes occurring in a system that is thermally isolated from its surroundings are such that its entropy never decreases.
“This behavior corresponds to the fact that entropy is a measure of the disorder of a system. On average all of nature proceeds to a greater state of disorder. Examples of irreversible progression to disorder are pervasive in the world and in everyday experience. Bread crumbs will never gather back into the loaf. Helium atoms that escape from a balloon never return. A drop of ink placed in a glass of water will uniformly color the entire glass and never assemble into its original shape.
“. . . This progressive tendency of nature toward disorder has been considered by many scholars as one of the primal natural processes that serve as a gauge for the irreversible nature of time. Accordingly, a considerable number have identified the relentless increase of entropy with what they term the thermodynamic arrow of time. In addition, the degradation associated with the increase of entropy has been discussed by some scholars of science and religion as a meaningful metaphor for evil.”