Thursday, July 04, 2013

Motivating a 'Hybrid' Epistemology

I guess I ought to make a point of announcing on my blog that my book with Ben Jarvis has finally been published. (That's UK only at the moment; it'll be worldwide later this month.) Here's OUP's official page. There were some delays with the printing that pushed things back a month or two longer than expected, but on the whole, I'm very pleased with the experience we had with OUP.

One of the central themes in The Rules of Thought is that there is an important sense in which the norms of rationality are objective: they apply universally to all thinkers, regardless of the subjects' rational limitations. We're motivated to say this in significant part because of cases of 'blind irrationality' -- situations where subjects fail with respect to rationality, in a way in which no intuitions or inclinations alert them to their error. There is an important sense in cases like this in which these are genuine failures of rationality; therefore, in this sense, the demands of rationality are not relative to the subject's limitations. The subject is doing the best he can do, given his limitations. This motivates us to the fairly strong view that for 'rational necessities' -- roughly, those truths that someone might want to call 'analytic' or 'conceptual' or maybe 'a priori' -- subjects always have conclusive reason to accept them. That is, everyone always has propositional justification for all of these truths. For example, my grandmother has propositional justification for every arithmetical truth. This is surprising to many, but Ben and I have arguments in the book that I think really do show that this has to be right.

But there is a puzzle that comes from this way of setting things out. It's a puzzle that's brought out really nicely in this new paper by Sharon Berry, "Default Reasonableness and the Mathoids." (Her target isn't views like ours, but the intuitions she's trading with are poignant for us.) We think that complex arthmetic truths -- Fermat's Last Theorem, for instance -- are always propositionally justified in the same way that simple ones -- 1+4=5, for instance -- are. But if this is right, it's not straightforward to make sense of the intuition that simple arithmetical premises are legitimate starting places in proofs in a way that complex arithmetical premises are not. Berry's central thought experiment involves the Mathoids, who find Fermat's Last Theorem (or other complex truths) immediately, primitively compelling in the way that we find simpler truths. She observes that it's intuitive that their proof method is unjustified, but argues that it's hard to find a principled difference between them and us. This seems to me exactly right.

The solution Ben and I have been thinking about -- this is discussed briefly in the book, and at greater length in a paper we're working on -- is that we need a 'hybrid' epistemology. We're still convinced by the arguments mentioned above that there must be an important epistemic element that doesn't depend on any of the contingencies of human psychology. To this extent, we're committed to the falsity of a thoroughgoingly virtue epistemology according to which epitsemic competences are the only fundamental epistemically normative element in town. But the virtue story also has something importantly right: the story we tell about propositional justification can't be the whole story either. The messier, psychology-laden doxastic justification story can't be given entirely in terms of propositional justification. We need to say something more contingent, about how the belief is formed. Virtue epistemology seems promising -- we want to say that there are virtuous traits and vicious traits, with respect to believing what is propositionally justified, and that these make a difference for doxastic justification and knowledge. The challenge, of course, is to describe in what these virtues consist. (If you want to distinguish us from the Mathoids, reliabilism is a clear non-starter.)

We have some tentative ideas for how this might go, but I'll save them for later. The main point of this post is to suggest that there's strong reason to think we might need two independent stories here: one for 'pure' epistemic statuses like propositional justification (the minimalist story that is a main theme in our book) and one for 'impure' epistemic statuses that bring in the psychology (the virtue story we're thinking about now). Neither will do on its own.

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