Barry Miller critiques the claim that per se causal series are necessarily finite, saying that every explanation is relative to something taken as a brute fact, and that there is no reason for such a series to terminate, even if it is a per se causal one. He’s right in the sense that we might, for all we know, keep finding per se movers forever, or perhaps even hit on a proof that we must keep finding such things forever. Perhaps the body moves so far as it has a force, but this force moves so far as it is energy, and the energy moves so far as it is mass-energy, and so on forever, with higher and higher levels of physical unification and transcendence. Leibniz argues either for this or a variant of it. Miller still argues that some causal series terminate, and do so in a way that makes a cosmological argument, but he denies that a per se causal series is necessarily one of them.
But Miller is muddling unexplained facts with inexplicable ones, since any explanation might be said to trace back to the first, but only the second are brute facts. If all “brute” fact means is one which we are not giving an explanation for, then we can make any fact such by simply remaining silent or dropping dead after we utter it.
But my main objection is that explanations don’t trace back to brute facts at all, since to say that they do commits the fallacy of the accident. No one seeks to rest an explanation on the unexplained or inexpicable, even if the thing he is targeting will necessarily have such a property. Saying that the one explaining is looking for the unexplained is like saying that a man who wants a wife is looking for a non-abstraction, or someone looking to make chocolate cake is looking for non-mustard. No one looks for the brutish or non-explained when he makes explanations, but for what is axios or worthy of serving as a starting point. You might push an explanation only so far, but you don’t choose to stop when you hit brutishness but when you hit on something axiomatic in a given domain, or at least for something that doesn’t assume the existence of what you’re trying to explain.
It’s this latter sense of explanation that is at work in the causal series that STA uses in his cosmological arguments. St. Thomas – like everyone giving explanations – isn’t targeting a brute fact as an explanans but something that can account for some fact of experience without assuming it.
But even if all this talk of brute facts wasn’t the fallacy of the accident, there is the broader problem whether any such things exist at all. in practice, they seem to work as justifying a stoppage of thought – hey, if you get to yell “brute fact!” at some point, why not yell it at nature and not God? But this is a ridiculous account of explanation, and one that ends up at odds with itself, since no one sees the point of explaining as to find something rationally impenetrable to rest logical consequences on. If it comes to that, there’s no reason to attempt explanations in the first place. After all, if what your’e targeting is what lacks a rational account, you’ve got that before you even bother giving an account at all. If the point of explaining was to get to brute facts, what you start with is as good as anything else.