Entropy

Abstract

The definition of an abstract quantity, entropy, which resolves itself as a property of a material system, makes possible a more elegant approach to the many ramifications of the second law of thermodynamics, together with a more subtle assessment of the performance of devices operating on an energy conversion basis. The concept of entropy also figures in a number of broad philosophical arguments, and the sense of direction that results from its natural tendency to a maximum value has led to Eddington’s description of entropy as ‘time’s arrow’.