The Human Question

Aristotle points out in Book I, chapter 1 that a plurality of natures is a necessary condition for substantial change to be able to occur.  Why, because new substances/natures come into existence when things of different kinds are combined: "... when things are combined htere is coming to be, and when they are dissolved there is perishing." (314b8) It's obvious that this would (rightfully) seem to be the case at Aristotle's time, for organisms are always made of non-uniform parts.  But we could say the same today on the basis of what we know about atoms, they differ in kind because they consist of different combinations of parts.

Always try to explain as much as you can my means of the discipline in which you are engaged, while being open to the possibility that there are some things that can be explained only by another discipline than your own.

James McWilliams is trying hard--too hard-- to convince the reader that Aquinas believed in momentum/inertia before Galileo ever came up with it. I ain't takin' his word for it, but I will look up the passages that he cites. They include the Commentary on the Physics VIII, lec. 22, where St. Thomas says that "the last quantity of energy is in the stone itself and is spent on the resistance of the object struck.  Here we have our whole doctrine of inertia." Huh? He also points out (on p. 13) that Aristotle was aware that more effort is needed to get an immobile thing moving than to keep an already-moving thing at the same velocity.  "In fact, that this phenomena was discussed  appears from the Mechanica  (intended to complete the Physics ), where we read: 'why is it that a body which is already in motion is easier to move than one which is at rest?'" (see ch. 32 858a3). Fr. McWilliams also accuses Galileo of misrepresenting Aristotle's s

De Generationibus Book I, chapter 9 makes an interesting claim (if read it correctly and remember correctly what I read).  It argues against the pro-Socratics on the basis that they could not explain efficient causality, i.e., the action/passion relation, precisely because they don't make the distinction between act/potency.