Modal Epistemology

van Inwagen isn’t noted as an epistemologist, but he’s a modal skeptic. I thought I’d post the view, and see what people might have been working on in this area that I don’t know about.

The view is not about epistemic modals, but about modal claims of, as Plantinga puts it, the broadly logical sort. Most call this modality ‘metaphysical modality’. I can’t recall exactly the extent of vI’s skepticism, but for purposes here, I propose to talk only of metaphysical modals that are not logical modals. About these, vI holds, I believe, that we do not have the epistemic powers necessary for knowing the truth value of such claims.

There seem to be obvious counterexamples to this skepticism, however.

I know that nothing can be completely red and completely green all over, and I don’t think this is a logical truth (i.e., provable in the, or a, correct modal logic). Other cases are harder to assess. For example, take any counterfactual that is not a logical truth or falsehood. Then append a possibility operator to it. If the counterfactual is true, then the possibility claim is true as well. So take the false counterfactuals. The possibility claim will then be a metaphysical modal, but I think I know that many of these are true. For a specific case, consider the counterfactual “If Rhode Island were within the present boundaries of Texas, it would be a county instead of a state.” That’s not a true counterfactual, but it is metaphysically possible that it’s true, and I think I know that this is the case, but I’m less confident about the knowledge claim here than in the above case.

So I think vI’s position is not discriminating enough. I know Paul Tidman has written on this issue, but there must be other sources as well?


Modal Epistemology — 2 Comments

  1. van Inwagen’s is a very interesting paper, and I just happen to have the reference to it handy:

    “Modal Epistemology,” Philosophical Studies 92 (1998): 67-84.

    And here is just a taste of its content:

    Philosophy abounds in modal arguments. A surprisingly high proportion
    of these arguments have the following features: they are
    formally valid; one of their premises is far more controversial
    (doubtful, disputable, problematic) than any of the others; it is a
    modal premise.
    In all the most interesting arguments of this sort, the “crucial”
    modal premise is an assertion of possibility, a statement of the form
    ‘it is possible that p’â?¦.

    Here are three examples of interesting arguments whose crucial
    premises are assertions of possibility:â?¦.

    Let us call such arguments “possibility arguments.”…
    Each of the three arguments I have laid out has had its advocates. But I know of no case
    in which a possibility argument has turned an atheist into a theist,
    a materialist into a dualist, or a theist into an atheist; I know of no
    case in which a possibility argument has changed any philosopherâ??s
    mind about anything. No one (I think) would now dispute the logical
    validity of the three possibility arguments. I have laid out; but a
    philosopher who rejects the conclusion of any of them will simply
    â?? I know of no exceptions to this generalization â?? reject (or at least
    refuse to accept) the crucial modal premise of the argument that has
    the unwelcome conclusionâ?¦..

    My own view is that we often do know modal propositions, ones
    that are of use to us in everyday life and in science and even in
    philosophy, but do not and cannot know (at least by the exercise
    of our own unaided powers) modal propositions like the crucial
    modal premises of our three possibility arguments. I have called this
    position “modal skepticism.” This name was perhaps ill-chosen,
    since, as I have said, I think that we do know a lot of modal
    propositions, and in these post-Cartesian days, “skeptic” suggests
    someone who contends that we know nothing or almost nothing. It
    should be remembered, however, that there has been another sort
    of skeptic: someone who contends that the world contains a great
    deal of institutionalized pretense to knowledge of remote matters
    concerning which knowledge is in fact not possible…..

    …All these things we can do. All these capacities we have. But
    I should say that we have no sort of capacity that would enable
    us to know whether the crucial premises of our three possibility
    arguments are true — or whether it is possible for there to be a
    pure, phenomenal color in addition to red, yellow, green, and blue,
    whether it is impossible for there to be a three-inch-thick sheet of
    solid iron that is transparent to visible light, or whether it is necessary
    that the laws of physics have the same structure as the actual
    laws. To my mind, philosophers who are convinced that they can
    hold, say, the concept of transparent iron before their minds and
    determine whether transparent iron is possible by some sort of intellectual
    insight are fooling themselves.

    I remember being bothered by a couple of cases that sprang to my mind of possibility arguments that PvI himself accepted — or at least accepted insofar as the possibility premise went — as good, though I was skeptical of the possibility premise. I wondered why this didn’t amount to “modal dogmatism” on PvI’s part. One was the fine-tuning argument for God’s existence. As PvI formulated it (in METAPHYSICS), it includes a premise to the effect that the constants in the basic physical laws are contingent — that it’s possible that they could have been otherwise. But that premise seemed fine to PvI, and he had little patience for the suggestion that those constants might be necessary. Here I thought it was PvI who might be fooling himself. I don’t claim that the constants are necessary, but even after reading PvI’s discussion, I saw absolutely no reason at all for taking either position (either the position that they could or the position that they couldn’t have been otherwise). The other was Plantinga’s free will defense, which utilizes a possibility claim to the effect that it’s possible that all creaturely essences should have suffered from transworld depravity. I think PvI again has no problem with that premise (and many accept this as a very succesful argument), though I have long thought that once you see what’s really involved in TWD, we should all be extremely suspicious of that particular possibility claim. (Interested parties can see my old — it’s one of my first — paper, “Plantinga, Presumption, Possibility, and the Problem of Evil,” CJP, 1991.)

  2. Dang, Keith, I hope you didn’t have to type in the entire quote! Anyway, it’s very helpful; I had forgotten that PvI uses ‘skeptic’ in a different sense than I usually do. Your point about the contingency of the basic physical laws is good, too. I share Peter’s view that this is an obvious truth, but I’m not much of a modal skeptic. One way of arguing for this point is to note that scientific reasoning often proceeds in terms of considering what would happen if the laws had been different, and it’s difficult to make sense of this reasoning if the hypotheses in question aren’t possible.

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