The Fourth Way, remixed

I’m playing with a reading—or perhaps remix—of Aquinas’ Fourth and Fifth Ways as giving a theistic solution to a problem that non-theistic Aristotelianism has no solution to. In this post, I will discuss the Fourth Way, and in the next, the Fifth.

The Fourth Way starts with the principle that degreed predicates, predicates where it makes sense to talk of “more” and “less”, are predicated in comparison to a maximal case. Infamously, however, given modern science, Aquinas’ down-to-earth illustration of that principle, namely that heat is predicated in comparison to the maximal case—allegedly, fire—is not not an example of the principle, but is actually a counterexample to it. There just is no such thing as maximum heat.

But nevermind heat. Aquinas wants to apply the Fourth Way to goodness. Now, the Aristotelian system that he has adopted already has an account of the good: a thing is good to the extent that it fulfills its proper function, a proper function that is defined by the thing’s form. Note that this account, too, does not match Aquinas’ gradation principle: unlike in Plato, forms are not self-predicating, so rather than the Form of the Sheep being the most ovine thing possible, the Aristotelian form of the sheep is immanent in each sheep, directing each sheep to an ovine perfection that no object actually meets.

But the Aristotelian account of the good is incomplete. While it allows us to compare the goodness of things within a kind—the four-legged sheep better fulfills its form than a three-legged one—there are also meaningful value comparisons between kinds. When Jesus says that we are “worth more than many sparrows” (Mt. 10:31), what he is saying is entirely commonsense. The human has much more good than the sparrow. The sparrow has more good than the worm. And the worm has more good than a mushroom. There really is a something like a great chain of being in reality. These comparisons, however, are not simply grounded in the immanent forms of things. The form of the worm need make no reference to mushrooms, nor that of a mushroom to worms.

Note that these interspecies value comparisons not only cannot be read off from the immanent forms, but sometimes they are in a kind of tension with the immanent forms. An earthworm’s form limits the neural development of the worm. Were the worm to grow a brain as big as a dog’s, it wouldn’t be able to burrow as well. And a mushroom that walked around would fail to be properly rooted as a mushroom ought.

Interspecies value comparison is a genuine problem that Aristotelianism faces, though some Aristotelians are willing to bite the bullet and deny the meaningfulness of such comparisons. Platonism did not face this problem—it could just talk of varying degrees of participation in the Form fo the Good—but Platonism lacked a satisfactory solution to the problem of intraspecies comparisons (Platonism’s solution would be to posit a self-exemplified Form for each species, which would involve the absurd idea that there is a perfect Sheep, which somehow manages to be both a sheep and immaterial, and we have all sorts of silly questions about whether it is male or female, what color it is, whether it has an even or an odd number of hairs, etc.)

A theistic Aristotelianism, however, has a solution to the problem of interspecies value comparison, in addition to non-theistic Aristotelianism’s solution to the intraspecies’ problem. There is a great chain of being defined by the ways in which the various species participate in the being that has all perfections. The human exemplifies intellection, the sparrow approximates omnipresence through rapid movement and exemplifies a significant degree of intelligence, the worm approximates omnipresence less well and has a lower degree of intelligence, while the mushroom at least exemplifies life. What grounds the goodness of these qualities independently of the forms of the things they are found in, and what makes for their axiological directionality (more intelligence is better than less), is then comparison to the maximal case, namely God.

Note that while this gives something like a great chain of being, it need not exactly be a great chain of being. We should not seek after a strictly total ordering—a partial ordering matches intuition better.

I don’t have a knock-down argument that theistic Aristotelianism is the only good Aristotelian solution to the problem of interspecies comparison. But it is a very good solution, and so once we have accepted basic Aristotelianism, it gives us significant reason to adopt the theistic version.

An earlier, more compact, version of this argument is here.