Project work

Decision making under indeterminacy (new draft)

Sometimes we’re called upon to make a decision between two options whose value depends on whether or not p; where we know that there’s no fact of the matter whether p. This presents us with a quite distinct decision puzzle. This paper explores the hypothesis that the appropriate response to such a situation is to make a judgement-call, and opt for one or the other arbitrarily. I show how this can be understood in terms of the currently-fashionable notion of imprecise or mushy mental states (especially: mushy desire). I show that the idea of groundless judgement calls motivates a framework which then gives attractive diagnoses of the appeal of the argument-form and forced march sorites.

Classical indeterminacy (rough draft).

This paper (currently being reworked) will (eventually) discuss the idea of a sincere non-epistemic classicism about indeterminacy. I argue this leads to indeterminacy in normative status—it’s indeterminate what you should or shouldn’t believe; and so what you should or shouldn’t do. By distinguishing between rational permission and immunity from neutral criticism, I argue that this motivates exactly the view on the cognitive role of indeterminacy discussed in the “decision making” paper above—specifically the “mind-making” version therein discussed.

 Nonclassical minds and indeterminate survival (new draft).

The papers above study the structure of nonclassical rational belief in the abstract. In this paper, I look at how their significance in a concrete case: that of vague personal identity. Parfit argued that future persons matter to us from a self-interested perspective to the extent they are psychologically connected to us. He argued that this was inconsistent with personal identity mattering in survival; but Lewis proposed a framework that would reconcile the two. I show that for the reconciliation to work, one has to commit to a quite distinctive understanding of the cognitive role of indeterminacy—one that cannot be read off the formal skeleton that Lewis provides. I go on to elaborate this nonclassical theory of mind with an account of epistemic modality, emotional attitudes, and rational all-out belief.

Gradational Accuracy and non-classical semantics“ Review of Symbolic Logic (2012).

Jim Joyce’s accuracy-domination argument shows that if our beliefs are improbabilistic (violate the constraints of probability theory) then they will be needlessly inaccurate, hence flawed. The argument depends on the measurement of “accuracy” meeting some formal conditions that Joyce articulates. But—I argue—it does not require any assumption about the character of the “worlds” at which accuracy is assessed. We can evaluate the accuracy of a belief state at nonclassical worlds, and the same Joycean reasoning goes through. This gives an accuracy-based argument for generalized probabilism. Drawing on work by Jeff Paris, I argue that the project of axiomatizing these probabilities gives us tools systematically to identify a normatively significant nonclassical logic.

“Generalized Probabilism: dutch books and accuracy domination” Journal of Philosophical Logic (2012)

This paper looks at the geometrical background common to (a special version) of the Accuracy Domination argument discussed above, and the famous Dutch Book argument. Both can be shown to hold in a very general setting, where the “worlds” at which bets are resolved or accuracy evaluated may involve nonclassical truth values (in the case of Dutch Books, the observation is due to Jeff Paris). I show that diachronic dutch book arguments (and generalized reflection principles) also go through in the generalized setting, and relate this to nonclassical formulations of conditionalization.

Non-classical logic and probability (for volume on the philosophy of probability, Hayek and Hitchcock, eds.)

I review the relationship between probability as a theory of rational belief and nonclassical logic/semantics. In addition to the results mentioned in the two papers above, I discuss (synchronic) conditional probabilities and formulate a generalized nonclassical decision theory. I lay out a set of challenges for future work.

Indeterminacy and Normative silence“ Analysis (2012)

In the papers above, I’ve characterized a whole variety of approaches to nonclassical phenomenon. On might think I have been exploring a space of views, all-but-one of which find no application. In this short note, I argue for an alternative picture. We should be pluralists about the cognitive role of indeterminacy—indeterminate conditionals, indeterminacy about the future, borderline cases and the like have different associated cognitive roles. If there is this deep difference in the way we think about indeterminacy, why do we give them a common label? I argue that the solution is to be found in Tim Maudlin’s idea of a nonclassical “third status” as involving a distinctive lack of general alethic normativity. This opens up space for a host of local modus vivendi—the plurality of local cognitive roles for indeterminacy we observe.

Related and background work: metaphysical indeterminacy

  • (with Elizabeth Barnes) “A theory of metaphysical indeterminacy“ Oxford Studies in Metaphysics (2011, Karen Bennett and Dean Zimmerman, eds.)
    Metaphysical indeterminacy—indeterminacy in the world itself—is often regarded with suspicion, and sometimes viewed as committed to the “liberal chic” of nonclassical logic. We argue that it shouldn’t be suspicious; and construct a fully classical model of the notion.
  • (with Elizabeth Barnes) “Vague parts and vague identity” Pacific Philosophical Quarterly 90:2: 176-187. June 2009. Penultimate Draft
    Does (metaphysical) vagueness in the parthood relation lead to problematic vagueness in identity (as Weatherson has recently argued)? We show  that the de dicto determinate truth of classical extensional mereology does not support this inference. De re modifications of the framework may allow it to go through, but the theorist of metaphysically vague parthood may reject them.
  • Multiple actualities and ontically vague identity”Philosophical Quarterly 58(230): 134-154 (January 2008).
    Evans’ reductio of vagueness in identity plays a pivotal role in the debate about whether indeterminacy in the world makes sense. I show that the standard way that linguistic theories of vagueness evade his argument also extends to metaphysical theories of vagueness.
  • “Ontic Vagueness and Metaphysical Indeterminacy”; Philosophy Compass, vol 3, 2008.
    A survey of the idea of vagueness/indeterminacy in the world. What motivates it? What are the leading objections?

Related and background work: the logic of indeterminacy

  • “Supervaluationism and logical revisionism”The Journal of Philosophy, vol.CV(4), 2008. Penultimate Draft
    Williamson argues that supervaluationalism is importantly logically revisionary. I argue that it isn’t. And if it is, it’s only unimportantly so.
  • “Degree supervaluational logic” Review of Symbolic Logic (August 2010). Penultimate Draft
    There are many ways of defining a “logic” from the resources available in a supervaluational setting. This paper looks in detail at the one involved in the “Nonclassical minds” paper, above. It turns out to be very odd.

Related and background work: general