Aha! Comes the dawn!
Early on in my Aquinas blogging I joked that if I ever wrote a philosophy book, it would be entitled “What Aquinas Takes For Granted,” and it would cover all of the points of Aristotelian thought that Thomas uses without explanation, for the benefit of those, like me, who came in late. But glory of glories, wonder of wonders, I no longer need to, for Peter Kreeft has already done it.
I recently received in the mail Kreeft’s book Socratic Logic, which is that most glorious of things, a college-level introduction to Aristotelian Logic. (Kreeft is a big fan of Socrates, as the title indicates, but though he is clearly fond of Plato I gather he considers Aristotle to be Socrates’ true successor.) And though I’ve just begun to read it I do believe that it is going to resolve a great many of my questions.
Just yesterday, for example, I got horribly confused by a passage in Thomas’ De Ente et Essentia about the relation between species and members of a species; and just this morning Kreeft began to explain some basic concepts that I had not understood.
I have been treating the term man as a species, as equivalent to the term rational animal; after all, “Man is a rational animal.” This is incorrect. Man is a term, a concept, the result of a simple apprehension. It is simple and indivisible. Rational animal is the species of man. It is clearly not simple and indivisible, as it composed of genus and specific difference.
What I was missing was the notion of the “five predicables”, the five kinds of things that can appear as the predicate of a proposition: genus, specific difference, species, property, and accident. These terms have to be thought of as predicates; and if I had realized this, I’d not have confused man and rational animal. These two concepts are related, but not identical.
I am just scratching the surface of Socratic Logic, but I can confidently say that it’s going to be an eye-opener all the way along.