Today I read Copleston’s History of Philosophy on Heraclitus, and the sixth chapter of Aristotle’s Physics with Aquinas’ commentary. I’m going to need to re-read both of these, so I’ll keep my comments brief.
Heraclitus surprised me. Copleston spends a fair amount of time on him, and frankly he sounds a lot more like a mystic than a philosopher. He says that Fire is the “ur-stuff” of which everything else is made, but he seems to say this almost on metaphorical rather than physical grounds.
As for Aristotle, I was surprised. Usually I find Thomas’ commentary more understandable that Aristotle’s text, but this time it was the other way around. (Of course, I might be fooling myself.) In any event, it appears that my conjecture was correct. When Aristotle talks of three principles, a pair of contraries and a substrate, he’s not say that everything we see derives from a single pair of contraries and a single substrate–not everything need be Fire. Instead, he’s saying that in every coming-to-be, there’s something that comes to be, the subject to which it happens, and its opposite.