<P> The second law of thermodynamics states that the entropy of an isolated system never decreases . Such systems spontaneously evolve towards thermodynamic equilibrium , the state with maximum entropy . Non-isolated systems may lose entropy , provided their environment 's entropy increases by at least that amount so that the total entropy increases . Entropy is a function of the state of the system , so the change in entropy of a system is determined by its initial and final states . In the idealization that a process is reversible , the entropy does not change , while irreversible processes always increase the total entropy . </P>
which law states that the entropy of the universe is always increasing
second law of thermodynamics