The big problem with this post by Will Wilkinson is not that he makes the Christian interlocutor a rather dim strawman — though he does that — but that he gives his Naturalist such a philosophically inept form of naturalism. Among the several philosophical errors Naturalist makes, the most significant is collapsing the distinction between moral and aesthetic judgment. He says, “All judgment functions like taste,” which might be true, depending on what you mean by “like.” But then he goes on to say, “Aristotle basically teaches that the practical wisdom is a matter of sensibility.” No, he doesn’t. Aristotle doesn’t teach anything remotely resembling that. Naturalist thinks if Aristotle agrees that moral judgments can’t be reached through an iron-clad chain of logical inferences and deductions, then all we have left is “taste” or “sensibility.” But that’s just wrong.
First of all, Aristotle didn’t have a concept of “taste” or “sensibility”: those are largely eighteenth-century ideas, stemming from the work Earl of Shaftesbury and Edmund Burke’s early essay on the sublime and the beautiful. Kant drew on these thinkers when in his Critique of Judgment he made the first really major contribution to aesthetics, the key to which is his belief that proper aesthetic judgments are “subjective universals.” But Kant, like every other serious philosopher, understood that we make our aesthetic judgments in very different ways and on wholly different grounds than we make our ethical judgments, which is why he also wrote the Critique of Practical Reason — a very Aristotelian book in many respects.
From reading Aristotle and Kant together, you can learn that moral judgments aren’t like the judgments of pure reason, but they aren’t like the judgments of aesthetic taste either. They are their own thing, and in making them we have to work really hard to develop the prudential wisdom necessary to apply general moral laws to unique particular situations. As Aristotle pointed out in the Nicomachaean Ethics, even the best laws are too general to interpret themselves, so we’ll always need people with practical wisdom (phronesis) and a sense of equity.
Naturalist, in Wilkinson’s dialogue, can’t see any real difference among the following judgments:
(a) The idea of eating pork grosses me out, so I won’t do it.
(b) I dislike pork.
© I think it’s wrong to be cruel to people.
For Naturalist, all of those are matters of “taste” or “sensibility.” In fact, none of them is a matter of taste or sensibility in the usual philosophical vocabulary. The first one isn’t even a judgment at all. And all of them are different kinds of responses made for different reasons. Naturalist can’t see those vital distinctions, and has to work with a simplistic binary opposition between “logic” and “taste”: “Morality just isn’t like logic, and the conclusions of moral arguments are pretty much never ‘rationally mandatory.’ Again, I’ve got Aristotle on my side. Morality isn’t much like math and it’s an elementary error to expect moral arguments to have the clarity and certainty of math or logic.” This statement makes one of the most elementary philosophical errors you can make, which is to conflate “logic” and “reason.” Aristotle never made that mistake, and in fact was quite clear in keeping the necessary distinctions, so Naturalist certainly doesn’t have Aristotle on his side. Just the reverse, in fact.
So before Naturalist can have a useful argument with Christian, Naturalist needs to read more philosophy. His simplistic binary division of the world of judgments leaves him with no leverage in the world of action. He can only say that some people have better taste than others, without being able to explain why or how this is so; still less could he try to make a case for following a particular moral path — say, the path of kindness rather than cruelty. Fortunately for naturalism, there are far better arguments out there than any that Wilkinson’s Naturalist makes. (But don’t tell anyone! I don’t want to give aid and comfort to the enemy!)