I hope Ralph won't mind if I piggyback on his post, but I'm just getting started on a paper that's partly about normative necessity, and I thought I'd get the old juices flowing with some PEA Soup discussion. (Plus it's February and my name starts with a D!)
The project is at the intersection of two dialectics. The first concerns normative necessity: Suppose you agree with Fine that metaphysical necessity is a matter of essence. And suppose you think (again, like Fine) that there are no essential connections between normative and non-normative properties. Then there are no metaphysically necessary connections between them.
Obviously, Ralph doesn't buy the second claim. I don't either. But I take it the majority of non-naturalists do. (From here I'll speak as though they all do just for simplicity's sake.) This means (for one) that non-naturalists have to reject supervenience as a metaphysical claim. But no worries, they can accept it as a claim about normative necessity. (Gideon Rosen has a nice paper where he tries to give a more thorough account of just what the heck this non-metaphysical normative necessity amounts to.)
That's dialectic the first. The other concerns the reliability of our normative beliefs. Lots and lots has been written about this (obviously), but I'm going to frame things in terms of a recent paper by Justin Clarke-Doane. Keeping it brief: There has been a lot of debate over whether or to what extent debunking arguments like Street's pose a threat to the reliability of our normative beliefs. Clarke-Doane points out that we need to distinguish the challenge to justify those beliefs from the challenge to establish their reliability. He thinks debunking arguments have no force whatsoever against the latter; indeed they might even help establish reliability. This is because Clarke-Doane thinks we should accept:
Modal Security: Information, E, cannot undermine our D-beliefs without giving us some reason to believe that our D-beliefs are not both safe and sensitive.
Our normative beliefs are safe just in case they could not easily have been false. If our normative beliefs are explained by evolutionary forces, then they are likely to be fairly stable across nearby possible worlds. So given that they're true (Clarke-Doane goes into why we are allowed to assume this, but I'll skip over it here), they're safe.
Our normative beliefs are sensitive just in case had the normative truths been different, our beliefs would have been different, too. No worries here, for there are no metaphysically possible worlds in which the basic normative truths are different.
The fruit is hanging pretty low here: The modal security of our normative beliefs is guaranteed in part by the metaphysical necessity of the basic normative supervenience relations. But on the Finean picture, those relations are not metaphysically necessary. Uh oh!
I think there's an obvious place to go here: Argue that (assuming Fine is right about metaphysical necessity) non-naturalists have to reject the metaphysical necessity of the basic normative truths. They can avoid giving up supervenience altogether by invoking normative necessity. But this comes with unexpected epistemological costs: They have lost one guarantor of reliability.
I think that's a fine argument (no pun intended), but it's not the one I want to pursue. Because I don't like Modal Security. I think that attempts to cash out our intuitions about reliability in counterfactual terms—e.g., via safety and sensitivity—fail in the face of metaphysical necessity. The fact that my true beliefs would be true in any world is not enough to satisfy my sense of what it is for my belief-forming mechanisms to track that truth when what explains why they are consistently true is not some link between my beliefs and truth but the fact that no matter how I got at the answer, it's true in all possible worlds. This is far from a new or original complaint, but I think there's more to say about it, and I think that there's something helpful about framing it in terms of these two dialectics. (I'm sure not everyone will agree, but it seems at least prima facie odd to me that changes in our understanding of what's going on solely at other possible worlds would affect our assessment of belief-forming mechanisms which operate entirely within the actual world.)
Ok, I'm tempted to say all sorts of extra things about how much I'm not an epistemologist and how there's plenty more to say about why I like framing it in terms of these dialectics, about whether this is really a worry about Modal Security or about the epistemological focus on reliability, and so on. But They keep encouraging us to write more exploratory posts, so I'm just throwing the line out and seeing what I can reel in...