May 2, 2006

Here’s a silly puzzle for you.

Regret seems like a factive emotion. You can’t truly regret that you forgot to feed the cat today if, indeed, you did feed the cat. If you did feed the cat and you forgot that you did, then it seems to you like you’re regretting not feeding the cat, but you’re as mistaken about your regret as you are about feeding the cat. You think you didn’t feed the cat and you’re sorry that you didn’t, but that’s not regret. Or so some people think, anyway.

Now, suppose that regret is factive like that. Then it’s plausible to think that the circumstance you’re regretting is in some way a ‘component’ of that regretting. (On this view, that’s why it’s factive: if the circumstance of my not-feeding-the-cat isn’t there, then I can’t be related to that circumstance in “regretful” manner.)

If this is the case, then it’s plausible to think that disjunctive regrets are a strange sort of thing. Regretting that p or q might be a relationship to a situation in which p is true (when it’s the truth of p that makes the disjunction true) or one in which q is true (the other case). A regret that p or q might be the same kind of thing as a regret that p (if p is the case) or a regret that q.

So, let’s suppose that in general, a disjunctive regret that p or q – since it is a regretting relationship to a circumstance in which p or q is true – brings with it a regret that p or a regret that q, since either the p-or-q circumstance is one in which p is true, or it’s one in which q is true. Call this the disjunction principle.

Now, it seems that regretting that (p and q) and regretting that (q and p) are no different to one another. Similarly, regretting that (it’s not the case that (p and q)) is no different to regretting that (either it’s not the case that p or it’s not the case that q) and so on. It seems a little bit plausible that if A and B are two statements that are logically equivalent then regret that A and regret that B don’t differ. Call this the equivalence prinicple.

Oh, suppose that the classical story of logical equivalence, that you were taught when you were taught truth tables, is correct. This is enough to get the puzzle going.

These things can’t all be right. Unless you have a lot on your mind. Here’s why.

Suppose you regret that p. Then, p is logically equivalent to (either (p and q) or (p and not q)). So, your regret that p means that you also regret that (either (p and q) or (p and not q)), by the equivalence prinicple. By the disjunction principle, you either regret (p and q) or you regret (p and not q). Suppose, without loss of generality, that it’s (p and q). Now (p and q) is equivalent to ((p and q and r) or (p and q and not r). So by the eqiuvalence principle … You see how it goes.

This is a version of the slingshot argument for regrets. Clearly, you shouldn’t believe the equivalence thesis (in its classical guise, at least) and the disjunction thesis for regrets. I’ve argued before in favour of the disjunction thesis and against classical equivalence for truthmakers.

What should we think in this case? Are either of the equivalence or the disjunction theses plausible? I’ve got my own ideas but I’ve written enough for one night.

(Thanks to Robert Anderson for getting me thinking about regrets and disjunctions and proposing something like the disjunction thesis. He thought of it when worrying about bets and regrets and Lloyd Humberstone’s puzzle mentioned in the previous post.)


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I’m Greg Restall, and this is my personal website. I teach philosophy and logic as Professor of Philosophy at the University of Melbourne. ¶ Start at the home page of this site—a compendium of recent additions around here—and go from there to learn more about who I am and what I do. ¶ This is my personal site on the web. Nothing here is in any way endorsed by the University of Melbourne.

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