Thursday, January 13, 2011

Just a brief note: I feel like I’ve been thinking the wrong way all along about the relationship between Newtonian celestial mechanics and Aristotelian physics. Thanks to Kepler, I keep trying to see Newton as having shown that Aristotelian motion-around-the-center is a special case of motion along a conic section. That’s very confusing, in part because there doesn’t seem to be any limit of Newton’s theory in which Aristotle’s is recovered. But it only just now occurred to me (perhaps I’m slow): it’s actually Aristotelian motion-toward-the-center which is shown to be a special case (i.e., Aristotelian fall is shown to be a special casus = Fall). The tendency to move toward the center is what Aristotelian’s call “gravitation,” so you might call Aristotelian physics — Aristotelian sublunar physics, that is — the theory of particular gravitation (assuming you could get Aristotelians to admit that all levitation is due to buoyancy).