Belief and Ability

Over at The Garden of Forking Paths Neil Levy has a nice counterexample to van Inwagen’s Belief in Ability Thesis.

I don’t have much to add since I think Neil’s case is basically decisive. But I’ll note that he doesn’t really need alien superscientists to get the example to work, only time travel. (Out of the metaphysical fire into the metaphysical frying pan!) If I’m a time traveller about to meet and talk to my younger self, I’m pretty sure there’s only one thing I am metaphysically free to say, namely what I actually said. But since I don’t remember what I did say, I don’t know what that is. And since this is probably going to be important I’m certainly going to deliberate about what to say.

5 Replies to “Belief and Ability”

  1. Maybe that’ll work too. But I don’t get a clear intuition with the time traveller case. In my case, one option is actually blocked, and will remain blocked, in yours there seems to be a sense in which the alternatives remain open. After all, the fact that my later self is talking to me now doesn’t actually change the fact that it is now true, at t that sufficent conditions for my saying whatever I will say at t1 are in place. So it’s not clear that the presence of my later self actually plays any role. If your case is a successful counterexample to BAT, then it should be true that the belief in determinism is by itself (rationally) incompatible with belief in BAT.

  2. BAT doesn’t say that if you deliberate about A and B then you’re metaphysically free with respect to each. It says that if you deliberate about A and B in the sense we specify then you believe you’re free with respect to each. Pointing out that in your example you are (plausibly) metaphysically free to do only exactly what you do is consistent with your believing that you are free with respect to many alternatives. No couterexamples in this neighborhood.

    And does belief in determinism by itself rule out acceptance of BAT? No. Double minded deliberation of various sorts if possible. One sort: I believe that what I do is what I’m determined to do, but deliberate (in the BAT sense) despite this: deliberators who accept determinism hold contradictory beliefs but that existential claim is no contradiction and, furthermore, it’s what we think is going on with anyone who really believes in determinism. This is covered in some detail in the paper itself.

  3. Neil, I think you’ve got Brian’s example backward—since one of us must be confused maybe it’s worth spelling it out. (Apologies in advance for going on at length.) I think it’s the later self who faces the problem.

    So: 2005-Weiner travels back to 1994. 2005-Weiner remembers that, in 1994, he (1994-Weiner) met a Weiner from 11 years in the future in an obscure CD store on Forbes Avenue. So when 2005-Weiner arrives in 1994, he doesn’t think about where to go—he just heads to the CD store, because he knows that’s what he’s going to do.

    Now 2005-Weiner is talking to 1994-Weiner. “What did I say to myself?” he thinks, racking his 11-year-old memories. “Am I going to tell 1994-Weiner about the incident with the pelican*, or not?” But he can’t find any memories about whether 2005-Weiner told 1994-Weiner about the incident with the pelican. “Well, should I tell 1994-Weiner about the incident with the pelican?” Now he’s deliberating. Say he does tell.

    Now we switch to the point of view of 1994-Weiner. “Aha!” he says. “2005-Weiner has told me about the incident with the pelican. Now I know that in eleven years I will travel back in time and tell my 1994 self this. It’s metaphysically determined.” And, let’s suppose, from 1994 Weiner maintains the belief that it is metaphysically determined that he will travel back in time and say whatever it is that he said—even after he forgot whatever it is that he said.

    So, ex hypothesi in the last paragraph, 2005-Weiner has the belief that he is metaphysically free only to say whatever it is that his 1994 self heard him say. But, as per two paragraphs ago, 2005-Weiner is deliberating about what to say. So that’s the counterexample.

    I can’t read Fritz’s paper on this computer, so I can’t say whether it is potentially a counterexample; but it does seem on its face to present a case where 2005-Weiner is not only metaphysically unfree but he believes he’s metaphysically unfree. (But it may not take care of the double-mindedness response.)

    *Not referring to any actual incident, as far as I can remember.

  4. Matt,

    You’re right; I got Brian’s case wrong (I was tired). But I’m still not sure that getting it right circumvents the objection. Compatibilists have often pointed out that we mustn’t confuse determiniation with constraint: the fact that I am determined to refer to the pelican incident doesn’t entail that I am constrained by anything to refer to the pelican incident. Determinism isn’t like a set of rails, which dictate that I go in a certain direction (of course, this is controversial; some incompatibilists deny it). Now, the nice thing about my case is that I do have an actual physical constraint, whereas in Brian’s it is instead a future event that is determined. So later Matt is deliberating, even though he knows that it is metaphysically determined whether or not he refers to the pelican incident. That’s exactly the situation in which current Neil finds himself in, even though he hasn’t met a time traveller (except that he hasn’t got an embarassing pelican incident to worry about).

    I’ve replied to Fritz about double mindedness over at GFP. Of course, having got Brian’s case wrong, I might have got his wrong too…

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