The Rules of Thought

Benjamin Jarvis and I have been working for some time now on a book manuscript on mental content, rationality, and the epistemology of philosophy. I posted a TOC of our first draft last summer. Since then, we've received some helpful comments from reviewers, and have revised extensively; we now have a full new draft, which we feel ready to share with the public. If you're interested, you can download the large (2.3 MB, 331 page) pdf here. Comments and suggestions are extremely welcome.

I'm including a table of contents of the new draft in this post, to better give an idea of what we're up to.

Modals and Modal Epistemology

I've just uploaded a new draft of my paper on modals and modal epistemology. (I posted an earlier draft a few weeks ago.) If anyone's interested, it's here:

Modals and Modal Epistemology

Comments are extremely welcome. I hope to submit it soon, so if you wanted to provide feedback in the next week or so, you'd be a total hero. But I'm interested to hear thoughts later, too, of course.

New draft paper on modals and modal epistemology

I've just completed a draft of a new paper on modals and modal epistemology, developing some of the ideas in my last few blog posts, and engaging with Timothy Williamson's discussion of counterfactuals and modal epistemology. Here's the abstract:

Modals and Modal Epistemology

Abstract. I distinguish (§§1-2) two projects in modal epistemology, and suggest (§3) that Timothy Williamson’s treatment of modal epistemology, relating truths of modality to counterfactual conditionals, is best understood as a way of addressing the mystery of why we should have developed cognitive access to facts of metaphysical modality. I offer (§4) a reconstruction of his argument, so interpreted. I compare Williamson’s counterfactual-based approach to metaphysical modality with a treatment in terms of quotidian modals (§§5-6), relating each to the dominant linguistic treatments of modals and conditionals (§§7-8). The insights offered by these linguistic treatments will emphasize the similarity of the counterfactual approach with the quotidian modals approach—in particular, they will demonstrate that the counterfactuals approach does not enjoy the advantage over the latter that Williamson claims for it. The ultimate lesson to be drawn (§9) is that there is a respect in which investigation into metaphysical modality is sui generis; but this is not a respect that renders modal epistemology implausibly mysterious.

The draft is online here. Comments are definitely very welcome -- feel free to email me, or leave a comment to this blog post, or get in touch with me in whatever other way seems like a good idea.

Williamson on modal epistemology and counterfactuals

This post is an exercise in Williamson exegesis. I'm looking primarily at chapter five -- the modal epistemology chapter -- of The Philosophy of Philosophy. (That chapter substantially overlaps a couple of earlier papers as well.) As many readers will know, Williamson emphasises the equivalence of claims of metaphysical modality with particular counterfactuals (such as the ones discussed in my recent post here), and suggests, therefore, that our ordinary imagination-based capacity for the evaluation of counterfactual conditionals brings along with it a capacity for knowledge of metaphysical modality. As Williamson says, "the epistemology of metaphysical thinking is tantamount to a special case of the epistemology of counterfactual thinking."

There are important interpretive questions that are too easily overlooked. The question I'm after right now is just: what in particular is Williamson trying to accomplish in this material? I think that many people are not always clear about this question. (Williamson is one of these people.)

One candidate project is to answer what I'll call the 'how' question:

How do we have modal knowledge?

A possible answer to the how question suggested by Williamson's work, which emphasizes the equivalence of modal claims with certain counterfactuals, is that we acquire modal knowledge by coming to have counterfactual knowledge, and exploiting the connection between counterfactual truths and modal truths. I think understanding Williamson's project in this way would be a mistake.

Counterfactuals and Modals

I like the approach to counterfactuals that treats them as modals. The sentence 'if A were the case, C would be the case' says that, out of some restricted class of possibilities, all the A possibilities are C possibilities. Which restricted class is in play is of course in part a context-sensitive matter. The relevant class of possibilities is relevant for other modal language, too. I've argued, controversially, that this is the case for 'knows'. But there are much less contentious cases, too. Consider bare modals like 'might' and 'must'; these definitely take context-sensitive domains, and those domains look to play central roles in the interpretation of counterfactual conditionals, too.

There is a kind of conflict between sentences like these, uttered back to back in a given conversational context:

(1) If he were to break thorough his chains, he would save the girl.

(2) He couldn't possibly break through his chains.

The 'kind of conflict' here isn't necessarily a matter of semantic inconsistency. (The approach to modals and counterfactuals I have in mind has the second entailing the first -- if there's no possibility of his breaking his chains, then, trivially, all possibilities in which he breaks through his chains are ones in which he kills his captors.) It's rather something like a pragmatic tension. The 'couldn't possibly' claim requires the modal base to be devoid of cases in which he breaks through his chains; such a base renders the counterfactual trivial -- so the counterfactual strongly prefers a context in which there are some chain-breaking possibilities among the modal base. (Compare: "There's nothing in this bottle." "All the air in the bottle is musty.")

Given this connection between bare modals and counterfactual conditionals, it's pretty straightforward to see that certain equivalences will hold as well. In particular, these two sentences will, in any given context, have the same truth value:

(3) He can't phi.

(4) If he were to phi, then p and not-p.

Draft monograph on rationalism

As you may have noticed, I haven't been posting here much lately. That's for a couple of reasons. One is that, as many of you will know, my personal life has lately been very exciting. Carrie Jenkins and I are recently engaged to be married. So that's pretty awesome. It also means I'm spending a good chunk of my time working on wedding planning.

The other reason I haven't been posting much is that, for all of this summer, and much of the past year, I've been, when focused on philosophy, focused on work on a co-authored book monograph with Benjamin Jarvis. That's been on a relatively grand scale, and didn't lend itself well to blogging. However, we now have a draft of a book monograph, and we're ready to give it a limited distribution to philosophers who might have comments and suggestions for us.

Our book is tentatively titled Rational Thinking: Philosophical and Quotidian. It offers a theory of mental content, a characterization of the relation between rationality and apriority, and a treatment of philosophical methodology. It is descended in fairly direct ways from the work we've done in our two previous co-authored papers, here and here.

If you're interested in having a look, email me and I'll send you the pdf. I'm placing a detailed table of contents below the fold, to better indicate the sort of topics we're covering.

Maybe now that we've gotten the manuscript to this stage, I'll find myself blogging on philosophy more often. I have an idea for a paper about the relation between modal epistemology and linguistic treatments of modality.

UPDATE 15 JULY 2011: new TOC and downloadable new draft available here. Old TOC below.

Rational Imagination and Modal Knowledge

Rational Imagination and Modal Knowledge, with Benjamin Jarvis. Forthcoming in Nous.

How do we know what's (metaphysically) possible and impossible?  Kripke-Putnam considerations suggest that possibility is not merely a matter of (coherent) conceivability/imaginability.  For example, we can coherently imagine that Hesperus and Phosphorus are distinct objects even though they are not possibly distinct.  Despite this apparent problem, we suggest, nevertheless, that imagination plays an important role in an adequate modal epistemology.  When we discover what is possible or what is impossible, we generally exploit important connections between what is possible and what we can coherently imagine.