Descartes' logic

“When I was younger, my philosophical studies had included some logic...”

I have to confess this is my biggest disappointment with D and many of his contemporaries. For such a tremendous period in philosophy, there is little of value achieved in logic. So much of what is thought of as logic is really advice for being reasonable, or rules for argument and debate. It’s the most barren period in the history of logic I can think of, given the extraordinary work going on in metaphysics and epistemology. And its even more striking given the explosion in maths (Leibniz and Newton and their weird competition over the calculus, most notably).

Now that I mention it, I wonder how unusual that moment was for logic. It’s the strangest thing, frankly.

Contrast this with the recent denial of the logic/rhetoric distinction (say, by Derrida and others). That denial is surely unsound, but it can only be made with any force in a context where the distinction is well-understood, or at least widely held, as it is in mainstream logic and philosophy in the twentieth century. D and his contemporaries, at least if the Port-Royal Logic is typical, did not widely believe in the (strong) distinction. The Stoics, the Aristotelians, the Platonists, by contrast, did make the distinction, and had to fend off the deconstructivists of their day, the Sophists, who denied it. With the distinction comes the denial, I guess. (Hmm—I’ll have to fact-check this more.)

“...I had to seek some other method comprising the advantages of [logic, geometry, and algebra] but free from their defects.”

Of course, by ‘defects’ here D means something like uselessness, or else that they do little to cultivate the mind. Here is more evidence for my reading of D’s theory of logic as guidance for good thinking.