The Philosophers' Cocoon

5 responses to “Modality without Possible Worlds”

1. eyeyethink

   June 27, 2013

   Thanks for the sharing Marcus; I hadn’t seen the Vetter and I’m glad to know of it.
   Yes, new actualism is definitely agenda-setting. But is it a good agenda? Well, like most anything, there’s probably some good and some bad. What is especially controversial is the supposition that scientific laws are metaphysically (not just physically) necessary. To my mind, that undermines one of the key reasons to distinguish between physical and metaphysical necessity in the first place (though other reasons remain).
   One wants to make sense of counterfactuals where the laws of nature are different. E.g., it is an important scientific truth that “if the strong nuclear force had been 2% stronger than it is, the physics of stars would be drastically different and life as we know it would not exist.” So folks usually say that the truth of such a thing is determined by a world that is not physically possible but still metaphysically possible. But with new actualism, there are no longer any metaphysically possible worlds with different laws. So how is the new actualist going to make sense of these counter-nomic statements? (We shouldn’t say that their truth is determined by worlds that are merely logically possible. For then the counter-nomic statement has the same modal status as any ole non-contradictory statement).
   My own proclivities are more Quinean, but I disagree with Fine’s statement (quoted at the beginning of Vetter) that Quine thought modal notions had no sense whatsoever. After all, Quine himself used modal notions in formulating his views (e.g., “any statement is revisable in light of recalcitrant experience”) But that is a whole other discussion.

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2. eyeyethink

   June 27, 2013

   (Erratum, Fine-style essentialists are not committed to the metaphysical necessity of laws; I should have spoke of dispositionalists instead of new actualists generally.)

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3. Marcus Arvan

   June 28, 2013

   eyeyethink: Thanks for your comment, as well as the erratum (I was about to write, in response to your first post, “Wait a minute: not all new actualists take laws to be necessary”, but now I don’t have to!).
   Anyway, I agree with your suggestion that there’s probably some good and some bad in the research program. Here are my thoughts at the moment. I think it is probably a mistake to do away with possible worlds altogether. Very different worlds are possible, and a bare form of new actualism can’t make adequate sense of this (given that they take modality to be determined by the nature of actual objects and properties).
   Here, though, is what I think the actualists have right: there are certain dispositions (or perhaps essences) that should be understood as constraining modal semantics in ways that a bare possible worlds approach does not. Allow me to explain.
   Here is what I think the new actualists have right. I don’t think it is metaphysically possible for me to jump tall buildings in a single bound. This is because I am made of protons, neutrons, and electrons, and it is metaphysically impossible for anything made of protons, neutrons, and electrons to do that.
   I think the new actualists are right in this regard because it seems to me that I, essentially, am made of these things. Something made of very different stuff wouldn’t be me. It would at most be someone like me.
   But I think we need possible worlds to make sense of that. I think it is metaphysically possible for someone very much like me — call him Super-Marcus — to jump tall buildings in a single bound. But I just don’t think it would be me. I think it would merely be someone like me.
   Anyway, traditional possible worlds theorists will say (as you suggest) that the first part of this collapses metaphysical and physical possibility. But this is what I think new actualists have right. There is a sense in which, given my essence, metaphysical modal truths about me are restricted by my actual composition. Where I think new actualists go wrong is in wanting to say this is all there is and get rid of possible worlds.
   In short, I’m inclined, at least for now, to think that neither traditional possible-worlds modal semantics nor new actualism are right. The right view, rather, is a combination of the two: a possible-worlds semantics constrained by dispositions or essences.
   What do you think?

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4. A.P. Taylor

   June 29, 2013

   Marcus, along the same lines, you might want to check out Williams and Borghini (2008) “A Dispositional Theory of Possibility” in Dialectica 62: 21=41.

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5. eyeyethink

   June 29, 2013

   Hi Marcus,
   Thanks for your remarks. It seems, however, that according to you the relevant modal truths are restrained not merely by your actual composition. It’s also that, apparently, they are restrained by the actual laws that govern your particle-parts (or at least some of those laws). But again, there seem to be important truths about what happens if such laws were different.
   Maybe there’s a trade-off and it’s ultimately better to go your route. But it seems you would be giving up something in the trade…

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