  But it is not, of course, the entropy of the whole universe with which the Second Law is concerned, but, rather, that of “small” systems temporarily energetically isolated from their environments. One can argue, in a manner tracing back to H. Reichenbach, that the entropic increase of the universe as a whole will lead, again using the usual time symmetric probabilistic posits, to a high probability that a random “branch system” will show entropic increase parallel to that of the universe and parallel to that of other branch systems. Most of the arguments in the literature that this will be so are flawed, but the inference is reasonable nonetheless.  It has also been suggested that if one invokes some underlying statistical dynamic law (such as the GRW law noted above), one need not posit a branch system hypothesis in addition to initial low entropy to derive the thermodynamic results.