Ed Feser, physics, and the Dunning-Kruger effect

Leah Libresco keeps recommending Ed Feser’s books, though I can’t fathom why. But it gave me the idea to try to write something about his books. So I opened my ebook copy of Feser’s Aquinas… and was quickly reminded that all of Feser’s “arguments” always strike me as blatant non-sequiturs, just like the original versions in Aquinas’ writings. There is, however, one thing that’s Feser-specific I can comment on: the way Feser makes a hash of modern physics.

Here’s Feser trying to defend one of Aquinas’ arguments against the possibility of a regress of causes (which I’ve already discussed at the previous link):

Aquinas’s example from the First Way of the staff which is moved by the hand is a standard illustration, and we can add to the example by supposing that the staff is being used to move a stone, which is itself moving a fallen leaf. Here the motion of the leaf depends essentially on the motion of the stone, which in turn depends essentially on the motion of the staff, which itself depends essentially in turn on the motion of the hand. For if any member higher up in the series ceases its causal activity, the activity of the lower members will necessarily cease as well. For instance, if the staff was to slip away from the stone, the stone, and thus the leaf too, will stop moving; and of course, if the hand stops moving, the whole series, staff included, will automatically stop. In this case the causal power of the lower members derives entirely from that of the first member, the hand. In fact, strictly speaking it is not the stone which is moving the leaf and the staff which is moving the stone, but rather the hand which is moving everything else, with the stone being used by it as an instrument to move the leaf and the staff being used as an instrument to move both stone and leaf.

…Causal series ordered per se are paradigmatically hierarchical with their members acting simultaneously, as in the staff example where the movement of the leaf occurs precisely when the movement of the stone occurs, which is precisely when the movement of the staff occurs, which is precisely when the movement of the hand occurs… since the lower members of a causal series ordered per se have no causal power on their own but derive it entirely from a first cause, which (as it were) uses them as instruments, there is no sense to be made of such a series having no first member. If a first member who is the source of the causal power of the others did not exist, the series as a whole simply would not exist, as the movement of the leaf, stone, and staff cannot occur in the absence of the hand.

What Aquinas is saying, then, is that it is in the very nature of causal series ordered per se to have a first member, precisely because everything else in the series only counts as a member in the first place relative to the actions of a first cause. To suggest that such a series might regress infinitely, without a first member, is therefore simply unintelligible. The leaf is “moved” by the stone only in a loose sense; strictly speaking, the leaf, stone, and staff are all really being moved by the hand. Thus to suggest that this series of purely instrumental causes might regress to infinity is incoherent, for they would not in that case be the instruments of anything at all (CT I.3). As A. D. Sertillanges put it, you might as well say “that a brush can paint by itself, provided it has a very long handle” (quoted by Garrigou-Lagrange in God: His Existence and His Nature).

This all sounds very intuitive, but it’s wrong. To see why, first imagine replacing the staff with a spring. And let’s suppose you’re pushing the stone along a smooth, low-friction surface, so that the force of your hand on the spring and the spring on the stone can both be constant. As you push the stone, the spring is compressed, but all the forces are steady so the spring isn’t going to make the stone go flying off. Forget about the leaf.

Now suppose you are very fast and slick, so that you can be pushing the stone along one instant (using the spring), and the next instant have taken your hand away so quickly it may as well have been instantaneous, leaving the spring momentarily in contact with the stone. What’s going to happen? Well, the spring is compressed, so it’s going to push off the rock and go flying. And according to Newton’s third law, the rock is going to get pushed. In fact, for a split second, the rock is going to get pushed exactly as if you’re hand was still there. It’s just not going to last, because the spring is going to go flying.

And if you understand physics, you’ll realize the situation with the staff and the stone is qualitatively identical. It’s just harder to see that that’s what’s going on, because a staff is a lot less elastic than a spring, which isn’t the same thing as being not elastic at all. But we know the two situations are really analogous, because the laws of electromagnetism say that the force that the staff exerts on the stone depends entirely on the relative positions of the protons and electrons that make up the two objects. The hand only matters because it will affect the future positions of the protons and electrons that make up the staff.

“But!” Feser will insist. The laws of physics can’t possibly matter here, because we’re talking about metaphysics! Except they do matter. Feser just doesn’t understand physics well enough to see that. And worse, his lack of understanding of physics leads him to imagine that as a philosopher, he knows that philosophical arguments are the way to determine whether he needs to know any science to do his philosophy, and the philosophical arguments have proven he doesn’t need to know any science, so he can be sure that anyone who tries to explain to him that he has his science wrong (and that this matters) is philosophically ignorant. That’s not a hole Feser can dig himself out of without learning more science, but he’s convinced there’s no reason for him to do that.

It seems like a rather nice example of the Dunning-Kruger effect.

"Atomsk - Yes, I think the way I feel about it is normal. I think ..."

Let’s talk about violent pornography
"The Scientific Method works by testing a hypothesis for implications, contradictions, and ridiculous/false results. You ..."

Pulling some devastating punches: a review ..."
"A bit OT: Found this article and it is imo closely related to the issue ..."

Let’s talk about violent pornography
"Just one thing for now, because it takes quite a bit of time to think ..."

Let’s talk about violent pornography

Browse Our Archives

What Are Your Thoughts?leave a comment