I asked Allan Gibbard this post’s titular question earlier this year, and he patiently noted that many people value consistency because if one has inconsistent beliefs, one or more of one’s beliefs must be false. I responded that since he and I believe that all normative beliefs are, in some sense, false, this sort of consideration wouldn’t give us — or other anti-realists about value — any reason to want our “ethical beliefs,” whatever form they might take, to be consistent. I can’t remember where the conversation went from there, but I don’t think that he was particularly moved by my response.
But I was moved by it, and I still am. Sure, if I believe P and not-P, I must have a false belief. But if there aren’t any normative truths, then if I believe P and not-P with respect to some normative matter, I should probably just stop having beliefs of that sort, but if I’m unable to stop (as some anti-realists seem to hold), what harm could follow if I have inconsistent beliefs about such matters?
I recognize that only certain varieties of “anti-realism” about ethics hold that there are no normative truths. Perhaps Allan’s “quasi-realism” isn’t one of them — I can never keep track of what he does or doesn’t think can be true — which might explain his not being impressed with this line of thought. But if one doesn’t think that there are any truths of the form “X is good,” “X is right,” “X is reasonable,” etc., then it seems one doesn’t have any truth-related reasons to value consistency among one’s normative commitments, beliefs, statements, etc.
Leaving that aside, here’s another little pseudo-problem: Suppose, like Sharon Street, you hold that “to make a normative judgment is to ‘give laws to oneself.’ As soon as one takes anything whatsoever to be a reason, one thereby ‘legislates’ standards according to which, by one’s own lights as a valuing agent, one is making a mistake, … if one endorses certain other normative judgments.” (This is from Street’s “Constructivism About Reasons,” pp. 229-30.)
I take Street’s account of reasons and normativity to depend largely on an appeal to internal consistency of some sort. According to Street, one’s judgments about reasons can be judged as “correct” or “incorrect” from the standpoint of all one’s other judgments about reasons. Of course, since Street also holds that there are “ultimately” no normative truths or truths about reasons, I’m inclined to ask why we should continue to make “judgments about reasons” or take ourselves to have reasons if we agree with Street that there are ultimately no truths about these matters. She has an answer to this, of course: We can’t help but occupy the “practical standpoint,” and occupying this standpoint necessarily involves making normative judgments and taking oneself to have reasons. I’m not convinced that she’s right about that, but I’ll grant it for the sake of argument.