Here is an observation by
Victor Reppert:
One interesting point about many ethical philosophies is that while they make no reference to a theistic God, they do seem to be grounded in metaphysics, and the kind of metaphysics at work is one that a modern naturalist would have trouble accepting. Plato, Aristotle, and the Stoics are prime examples. Plato's moral philosophy is based on the Form of the Good, which shares certain characteristics with the theistic God, and which can be known through a process of recollection where we recollect what we were aware of in a pre-existence. Aristotle is based on the idea of an inherent purpose for human life, and Stoic ethics is a response to Stoic metaphysics. No one seems to be suggesting that ethics will be all just the same regardless of metaphysics. Even if a personal God isn't required for ethics, doesn't it seem plausible that at the very least some sort of metaphysics is required that most naturalists today would have a hard time accepting. Is it reasonable to reject what Kant called a metaphysics of morals?
There's a good discussion going on in the comments section of Reppert's post. I think Reppert is right on this. The old apologetic claim that you can't have morals without God is not exactly right. The naturalist does indeed have some philosophical options for believing in a true, objective moral system in the absence of the Lawgiver of traditional theism. He can be a Platonist, for example, and there are other cognitivist ethical theories that posit some objective ground of moral facts that fit nicely with naturalism broadly defined (see
this book, which I recently started but have unfortunately had to set aside, for a nice roundup of the current metaethical scene). But Reppert's point is that the available options don't fit too well with "modern" naturalism, by which I assume he means the form of naturalism that is dominant in the sciences, which is very often
physicalist in character. When you start talking about abstract "facts" on a naturalistic worldview - facts like, "A square has four right angles," and, "It is wrong to toss little Jimmy into the well for laughs" - you have to do some wiggling to claim that the facts represent objective non-mental realities. A naturalist can't put a square, for example, in a test tube and study it. He can't do it with the moral fact proscribing the tossing of little Jimmy into the well either. So if he is going to say that these things are real in the same way that the chair I am sitting on is real, he has to monkey with his metaphysics so that immaterial realities can co-exist with the material realities.
Now, I don't want to go into the questions of whether the naturalists have good reasons to do this, or whether objections like
this by Reppert to their doing so are right. Let's say that such objections aren't very convincing, and that the non-physicalist naturalist is perfectly rational in accepting some version of objective, realist version of metaethics. I think that if he does this, he does so at a great price. It seems to me that if he can defend his belief in non-natural, immaterial, abstract facts such as the fact, "It is wrong to toss little Jimmy into the well for laughs," then he has forfeited his right to criticize the theist for her belief in an invisible, supernatural, immaterial God. It seems that whatever method the naturalist defends for coming to believe in abstract moral facts, the theist can also use to defend her belief in God. Suppose the naturalist says that moral facts are known
a priori. Well, why can't the theist do the same thing?
Let's go another route. Suppose the naturalist proposes some kind of
perception of moral facts. Suppose she says that we have a faculty for moral intuition that is analogous to our perceptual faculties like seeing and hearing, and that when I encounter a statement like, "Don't throw little Johnny into the well for laughs," the moral sense of
wrongness that I associate with that statement is actually my perceptive moral faculty kicking into gear. I simply "see" (as it were) the moral fact involved. Again, if this type of metaphysical and epistemological system is perfectly rational, why is a corresponding theistic system any less rational? In fact, Christians have been proposing a model like this for a very long time. The best recent formulation of this type of system is found in
the work of William Alston.
If I am right on this, the naturalist is caught on the horns of a dilemma. Either (1) she can say that it is rational on some version of naturalism to believe in the existence of objective moral facts
and that it is equally rational for the religious believer to accept religious facts (about God and His ways, etc.) in an analogous way or (2) she can say that it is irrational to believe in the existence of immaterial, abstract realities like moral properties and omnipotent Spirits, and that all such beliefs are only mental constructs that have been incidentally programmed into us by thousands of years of natural selection. But if she takes route (2) and admits that all of our moral beliefs are subjectively conditioned by natural selection and by the culture in which we find ourselves, she cuts off her own ability to make moral claims about "good" and "evil" with a straight face, because she knows that those words only refer (at best) to human desires.
I should point out that there are many naturalists - the so-called "friendly atheists" who are appalled by the pretentious screeching of Dawkins, Harris, et al - who have no trouble accepting (1). Although they strongly
disagree with religious believers, they wouldn't say that religious believers are irrational, or kooky, or dangerous, or whatever. But there seem to be very few of this type of naturalists these days. Or, if they really are out there, their voices are being drowned out by Dawkins and his gang.
