Library Concept
Entropy
A measure of disorder or uncertainty — Boltzmann's statistical-mechanical quantity, and Shannon's 1948 measure of information.
Entropy originates in thermodynamics, where Ludwig Boltzmann’s 1872 statistical mechanics related it to the number of possible microscopic states a system could occupy, formalized as S = k_B ln W. Claude Shannon adapted the same mathematical form in his 1948 paper “A Mathematical Theory of Communication,” defining information entropy as the average uncertainty in a variable’s possible outcomes and founding information theory. The name itself came from John von Neumann, who reportedly told Shannon to call his new measure “entropy” for two reasons: a mathematically similar quantity already carried that name in statistical mechanics, and — since “nobody knows what entropy really is” — Shannon would always have the advantage in an argument.