Clayton,

Careful with the modalities there. “Custer died at Little Big Horn but he might not have” is actually a sentence of a sort that we often say. For example, he might not have if he’d been a better tactician, or less of an asshole. It’s just that here “might not have” raises a counterfactual possibility for Custer, rather than a salient error-possibility for the belief about what actually happened, which is the sort of possibility that Duck’s point was about.

That quibble aside, I’m a bit confused by your reply. Are you siding with the view that you can’t raise the possibility that a belief of yours might be false, without thereby treating it as something other than a belief? Or with the view that you can? Because Duck’s view is apparently the former, but what you say about “I believe that Custer died at Little Big Horn” as vs. “Custer died at Little Big Horn” would seem to count in favor of the latter view, not the former.

It’s true that asserting that Custer died at Little Big Horn expresses a belief to the effect that Custer died at Little Big Horn. And it’s true that directly asserting that rules out raising an error-possibility for that belief. But it’s precisely when you not only express a belief but also say that you believe so-and-so that you can raise error-possibilities for the belief in question. And I certainly find it hard to believe that you treat P less as one of your beliefs when you say “I believe that P” than when you say simply “P.” You’re treating the belief as something you’re more ready to give up or revise; and you’re treating its truth as less than certain; but you’re not thereby actually giving it up, in whole or in part, or treating it as something other than a belief of yours.

Duck: “So (at least on the pragmatist cum Davidsonian view I recommend) we never say: this belief of mine might be false; for to say of something that it might be false is to regard the issue of its truth as no longer settled – and thus no longer a belief at all.”

Come on. One often says that a belief of hers might be wrong. For example:

L.W.: Why are the detective magazines so bloody expensive this month?

N.M.: I believe that there’s a paper shortage, but I might be mistaken.

What Moore reminded us of is that one never says that a (current) belief of hers is actually false. But one often admits the possibility that it might be. That’s not abandoning the belief; it’s just expressing some epistemic humility about the beliefs that you have.

In fact, it’s precisely in such moments of epistemic humility that we’re most likely to use the phrase “I believe that —,” instead of simply asserting the content of the belief without qualification.

I have no firm idea as to whether this grammatical point bears on anything of substance in your post, though. I believe it might, but you never know…