For you have not received the spirit of bondage again to fear; but you have received the Spirit of adoption, whereby we cry, Abba, Father. For ye received not the spirit of bondage again unto fear; but ye received the spirit of adoption, whereby we cry, Abba, Father.
Hence, entropy can be understood as a measure of molecular disorder within a macroscopic system. The second law of thermodynamics states that an isolated system's entropy never decreases. Such systems spontaneously evolve towards thermodynamic equilibrium, the state with maximum entropy.
The concept of entropy was introduced into the theory of thermodynamics by Rudolf Clausius in the 1850s. Clausius defined the entropy [math]S[/math] as a state function of a thermodynamic system, such that the infinitesimal change in the entropy of the system is given by.