In my last post, I examined Edward Feser's case for universals (and thus formal causes) and concluded that, while it is a strong case, it is not rationally unavoidable and can be answered. In this post, I'll discuss final causes, and explain why I think there is little reason to believe in the kind of final causes Feser needs to make his case for natural law.
Feser's case for final causes is spread throughout the book (and is discussed in many places on his blog), but the basic gist of it that the only way to make sense of why A regularly causes B is to say that A is inherently "directed toward" B as a goal. As Feser puts it:
But there is no way to make sense of these regularities apart from the notion of final causation, of things being directed toward an end or goal. For it is not just the case that a struck match regularly generates fire, heat, and the like; it regularly generates fire and heat specifically, rather than ice, or the smell of lilacs, or the sound of a trumpet. It is not just the case that the moon regularly orbits the earth in a regular pattern; it orbits the earth specifically, rather than quickly swinging out to Mars and back now and again, or stopping dead for five minutes here and there, or dipping down toward the earth occasionally and then quickly popping back up. And so on for all the innumerable regularities that fill the universe at any moment. In each case, the causes don’t simply happen to result in certain effects, but are evidently and inherently directed toward certain specific effects as toward a “goal.” As we saw when we first looked at Aristotle’s notion of final causality, this doesn’t mean they are consciously trying to reach these goals; of course they are not. The Aristotelian idea is precisely that goal-directedness can and does exist in the natural world even apart from conscious awareness (Kindle Locations 2208-2217).
Now, this may in fact be correct. It is certainly a better alternative to Hume's theory - the theory that there are simply successions of events, and that causation and regularity are simply things we project onto our experience of reality in order to make sense of things. Hume's theory is notorious for raising insurmountable skepticism about the reliability of induction and (therefore) the reliability of science itself; if causation is simply the succession of one event by another without any necessary connection between the two, then any event might in principle follow any other, and the regularities we see in the laws of nature could break at any moment. Final causes surely make causation and the laws of nature much more intelligible - at the very least, they are a serious contender for a comprehensive theory of causation.
The problem for Feser here is that the need to invoke final causes is much more limited than his conclusions require. He claims that (for example) the reason opium causes sleep is because it is inherently "directed toward" causing sleep specifically; unless we say that opium is inherently "directed toward" causing sleep as a final cause, we cannot make sense of why it does in fact cause sleep rather than something else or nothing at all. But in fact we can make sense of why opium causes sleep - chemistry and biology have already done the job. Feser anticipates this objection, saying that the chemical facts are only the mechanism by which opium manifests its inherent powers and achieves its final cause. But once the chemical facts are in place, the appeal to the final cause of opium becomes superfluous - given the facts about the chemistry of opium and the chemistry of the human brain, the fact that opium causes sleep falls out as a logical consequence. To put it technically, the fact that opium causes sleep logically supervenes on the facts about chemistry. We may have to appeal to final causes anyway to explain why the facts of chemistry hold, but we do not need to appeal to them directly in order to explain why opium causes sleep.
But do we need to appeal to final causes at the level of chemistry? The thing is... we probably don't. There is good reason to believe that, just as the fact that opium causes sleep logically supervenes on the facts about chemistry, the facts about chemistry logically supervene on the facts about basic physics. There is good reason to believe that, once the facts about basic physics are put in place, the facts about chemistry (as well as biology) logically follow. To see why, note that the laws of physics are supposed to be universal; they are supposed to apply to every particle in the entire universe equally, without exception. Unless acted on by a non-physical force (if any exist), the behavior of particles, even in interaction with each other, is not supposed to change - if it did, then the laws of physics would have been violated. So all of the dynamics of the material world (absent non-physical influences) should be explicable in terms of particle physics, including the behavior of composite objects. It follows, then, that the facts of chemistry and biology - which deal with structure and dynamics at the level of composite objects - should be logically supervenient on the facts about particle physics: given the facts about particle physics, the fact that opium causes sleep should be logically necessary. We may need to appeal to final causes to explain the laws of physics - and I think a good argument could be made for this - but to appeal to them at the level of chemistry or biology would simply be superfluous.
To be fair, Feser has addressed this issue in a blog post before, admitting that the position that formal and final causes exist only at the level of physics is a position that an opponent could logically take. But he claims that final causes (and thus formal causes too) must exist at the levels of chemistry and biology as well, as there are causal powers at those levels that are not reducible to the causal powers of fundamental particles. Being a layman who is not an expert in philosophy of chemistry or philosophy of biology, I will have to respectfully disagree with Feser's view. I submit that, if there are indeed causal powers at the level of chemistry and biology that are not logically supervenient on dynamics at the level of particle physics, then the laws of physics have been violated - something which Feser himself denies is possible when he dismisses Cartesian dualism in Chapter 5 (more on that later). To be sure, there are causal properties that are conceptually irreducible to those found in physics - to redescribe reproduction or metabolism at the level of physics would result in a complete loss of meaning - but to say that they are ontologically irreducible (that is, logically non-supervenient on physics) would be to commit oneself to the idea that many of the laws of particle physics no longer apply when particles are arranged in certain formations. And it is ontological reducibility that we are concerned with here; if chemistry and biology are logically supervenient on physics, then the appeal to final causes at those levels is superfluous regardless of whether or not they are conceptually reducible to physics.
So it seems that formal and final causes - the core of Aristotelian metaphysics - are not needed above the level of basic physics in order to make the world intelligible. In my next post, I will discuss the consequences this has for Feser's cases for hylomorphic dualism and natural law morality.
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