  Once this is said, it might be objected that we’ve more or less left the naturalism behind. We don’t need anything remotely like ethology to tell us that we should favor ethical views supported by good reasons over those not so supported. Nor do we need to be any sort of naturalists to believe it. And if we’re concerned with what is distinctively and characteristically human, we might legitimately follow Williams in asking why we should make such a big deal about rationality. Why not the making of fire, having sexual intercourse without regard to season, despoiling the environment and upsetting the balance of nature, or killing things for fun (Williams 1972, 73)? There’s a natural and obvious answer to this, which appeals to widely shared human commonalities of value. Perhaps we can bring this too under the heading of the characteristically human, but those humans who may not share these values might fairly retort, So what? Aren’t they free, for all this quasi-ethological picture tells us, to assign normative weights in their own ways? The hallmark feature that is distinctive of naturalism, Hursthouse would respond, is the regulatory role of the four ends (Hursthouse 1999, 224–226). But these too seem to be decidedly up for grabs, as when she acknowledges that nothing in particular need follow from her view about the ethical status of (e.g.) celibacy and homosexual sex (Hursthouse 1999, 215).