There are features of things which make moral judgments about them true. For instance, in a certain case it may be that the fact that a given act is an act of killing-for-fun is the feature of it which makes it wrong. It might be thought that there are some types of things which never have these sorts of features. For instance, it might be thought that the motions of inanimate objects never have these features. If so, then whereas any given human action might be wrong, or right, or permissible, or obligatory, or supererogatory, or whatever, the motion of any given inanimate object is never any of these things; such motions are "outside the moral domain," as it were, and no moral judgment is ever true of them. So for instance, on this view, while there are true moral judgments about Bush's decision to invade Iraq, there are no true moral judgments about the motions of Mars, since there are no features of that motion which would make any such judgment true.
A short argument against this view can be written as follows:
1. Either (a) the motion of Mars is morally permissible, or (b) the motion of Mars is not morally permissible.
2. (a) is a moral judgment.
3. (b) is a moral judgment.
4. Thus, there is at least one true moral judgment about the motion of Mars.
We can obviously extend this argument into any "domain" we please, and therefore we can show that there is no kind of thing about which there are no true moral judgments.
If we want to avoid the conclusion, what should we do? 1 has got to be true. 2 seems true enough; if I say something is morally permissible, I have certainly made a moral judgment (even though in the present case I've clearly made a false one). So 3 seems to me to be the premise we'll need to attack if we want to avoid 4. To deny 3 is to say that (b) (i.e. the claim "the motion of Mars is not morally permissible") is not a moral judgment. But there seem to be genuine moral judgments which take this form; for instance, it seems clear that (c) "Killing innocent children is not morally permissible" is a moral judgment. So we should want to say that (c) is a moral judgment, even if (b) isn't one. But there seems to be no principled way to get away with this. That is, there seems to be nothing about (b) which would keep it from being a moral judgment without keeping (c) from being one, too. It seems to me that if any sentence of the form "______ is not morally permissible" is not a moral judgment, then none of them are. If so, then a principled 4-denier should say that sentences of the form "_______ is not morally permissible" are never moral judgments. But that is an unpleasant thing to have to say.
A similar set of problems may obtain in other areas. We may be tempted to say, for instance, that while there are some sorts of things about which there are true "color judgments" (e.g. there are true color judgments about ketchup, such as the judgment "Ketchup is red"), there are other sorts of things about which there are no true color judgments. For instance, molecules are colorless, "outside the domain of color," so we might be tempted to say that any "color judgment" about a molecule has to be false. Similarly, no number has a color, so we may want to say that all judgments about the color of, say, 7, are false. But any molecule, and any number, is either green or not, and in either case it seems to follow that there is at least one true color judgment. So we'll be faced with the same pair of options: either (1) "X is not green" is not a color judgment, or (2) there are true color judgments about molecules and numbers.
I expect that, with regard to color judgments, it will not matter very much which of the two options we choose. Nothing much hangs on whether "X is not green" is classified as a color judgment or not. I am not sure, however, whether anything important hangs on the corresponding question about moral judgments. If we say that there are true moral judgments about dogs and planets and so on, it will follow that the sorts of features which make moral judgments true are features had by every type of thing. This might be an interesting result. Or, if we say that there aren't any true moral judgments about dogs, planets, etc., then we may be committed to say that "negative" judgments of the form "____ is not [permissible, obligatory, right, wrong, etc.]" are not genuine moral judgments. This again may be an interesting result.
