“A Real Knee-Slapper”

Edward Feser writes in The Last Superstition:

A particularly famous criticism of Aristotelian Scholasticism by early modern philosophers is enshrined in Molière’s joke about the doctor who pretends to explain why opium causes sleep by saying that it has a “dormitive power.” The reason this is supposed to be funny is that since “dormitive power” just means “a power to cause sleep,” the doctor’s answer amounts to saying “opium causes sleep because it has a power to cause sleep”; and this, it is said, is a mere tautology, and therefore explains nothing at all. (A real knee-slapper, no?) In general (so the objection continues) Aristotelian Scholasticism, in positing inherent causal powers, forms, and final causes of various sorts, merely peddles empty phrases of this sort instead of genuine explanations. The trouble with this objection, though, is that the statement in question, while admittedly not terribly informative considered all by itself, is not a tautology; it does have substantial content, even if that content is minimal. To say “opium causes sleep because it causes sleep” would be a tautology. But the statement in question says more than that,. It says that opium has a power to cause sleep; that is to say, it says that the fact that sleep follows from the ingestion of opium is not a mere accidental feature of this or that sample of opium, but derives from something in the very nature of opium as such. That this claim is by no means trivial or tautological is evidenced by the fact that the early modern philosophers rejected it as false. They didn’t say, “Sure, opium has a power to cause sleep, but that doesn’t tell us anything” (which is what they should have said if it really were a tautology). Rather, they said, “Opium does not have such a power, because there are no inherent powers, forms, etc.” Moreover, they couldn’t very well dismiss the appeal to power and the like as tautological on the grounds that such an appeal has only minimal content, because their own alternative proposal, when it too is considered all by itself, also has minimal content: To say “Opium causes sleep because the chemical structure of opium is such that, when ingested, sleep results” is hardly more informative than “Opium causes sleep because it has a power to cause sleep.” If the former statement is not a tautology — and it isn’t — then the latter isn’t either.

Of course, the critic of scholasticism is going to say, “But the reference to chemical structure isn’t supposed to be a complete explanation all by itself; it’s just a starting point, and detailed empirical investigation into the specific chemical properties of opium would be needed in order to give a fully satisfying explanation.” And that is perfectly true. But exactly the same thing is true of the Scholastic appeal to forms, powers, final causes, etc. Such appeals are not supposed to be the whole story. What they are intended to do, rather, is to point out that whatever the specific empirical details about opium turn out to be, the fundamental metaphysical reality is that these details are just the mechanism by which opium manifests the inherent powers it has qua opium, powers that a thing has to have if it is going to have any causal efficacy at all. This is perfectly consistent with, and indeed is (from an Aristotelian point of view) the only way to properly understand, the results of modern chemistry: The empirical chemical facts as now known are nothing other than a specification of the material cause underlying the formal and final causes that define the essence of opium. As elsewhere, the “critique” of Aristotelianism here rests on an unjustified double standard coupled with a failure to distinguish metaphysical issues from empirical ones. [180-181]