Irreversibility, Molecular Chaos, and A Simple Proof of the Second Law
  The irreversibility in a statistical system is traced to its probabilistic evolution, and the molecular chaos assumption is not its unique consequence as is commonly believed. Under the assumption that the rate of change of the each microstate probability vanishes only as time diverges, we prove that the entropy of a system at constant energy cannot decrease with time. 
P. D. Gujrati