The Complete Works of Claudius Galen, Vol. 18 Pt. 2

...[and that] afterward, concerning the particular details, it seems better to me to reserve all such matters for the explanations of the medical propositions of this book that we are about to undertake, especially because none of those who have interpreted this most necessary book has done so. For that in which Hippocrates desires the physician to be exercised, he has in this passage omitted, failing to show how one ought to make a prognosis of those things that have already occurred or are present, yet are not known to us through the senses. At the same time, [one must also] foresee if there is anything divine in diseases, and to learn thoroughly about this: what, after all, is this “divine” [element] of which he commands a prognosis to be made? On this point, those who have interpreted the book are in disagreement. For some think that illnesses come upon men through some wrath of the gods, and they indeed cite as testimony for this opinion [the accounts] from those who have written so-called histories, yet without [providing] arguments; nor do they demonstrate whether Hippocrates shared this opinion, which would have been the task of a good interpreter. For it is not the purpose of explanations simply to state whatever may seem to us to be true...