There is an interesting discussion at Public Reason about coming from both the discussion of David Estlund’s new book and a post by Nicole Hassoun about the role of the social scientific (using that term very broadly) evidence in political philosophy. I’ve got a lot of thoughts about that. Here’s one largely ad hominem thought.
There is (what should be) an unsurprisingly large amount of motivated cognition among philosophers when they think about this issue. This is of course the natural human reluctance (philosophers are people, too!) to diminish the importance, authority, or relevance of one’s own expertise. When it is suggested you might need to know, say, a good deal of economics or the literatures that actually compare the performance or real institutions, in order to be able to know confidently whether your argument for the welfare state or whatever goes through or not, one sees a tendency to either deny that you do need to avail yourself of the relevant bodies of knowledge (these people tend to defend strongly utopian political theorizing), to really let motivated cognition run wild and pretty crudely cherry-pick your way through a bit of the relevant literature, or some combination of quasi-a priorist soft utopianism and limited cherry-picking.
But shouldn’t it be impossible to take seriously an argument to the effect that, say this or that policy is required in order to secure the conditions for the development of some capacity, in the absence of (a) a well-empirically-grounded theory of the nature of that capacity and its development, and (b) some kind of actual evidence that this or that policy in fact has the kind of effect on it that one hypothesizes? I wouldn’t mind so much if political philosophy arguments were more often in the form of “Hey, here’s a conjecture! I suggest somebody competent to do so try to find out if it’s true.” I would be quite happy if I saw more “Hey, here’s a conjecture, and here’s a my attempt to honestly synthesize the relevant literature in a first pass at getting the answer.” That would be terrific. But usually, the argument aims to establish something substantive with an armchair, a Joe Stiglitz op-ed, and something remembered from the Tuesday Science Times.
Over just the past decade, moral philosophers have made huge strides in intelligently using, and even creating, findings in psychology. Political philosophers, I fear, have yet to catch up.