•  42
    Correction to: Agglomerative Algebras
    Journal of Philosophical Logic 49 (6): 1257-1257. 2020.
    The original version of the article unfortunately contained a few mistakes.
  •  75
    Noûs. forthcoming.
    Consider the sentence “Lois knows that Superman flies, but she doesn’t know that Clark flies”. In this paper we defend a Millian contextualist semantics for propositional attitude ascriptions, according to which ordinary uses of this sentence are true but involve a mid-sentence shift in context. Absent any constraints on the relevant parameters of context sensitivity, such a semantics would be untenable: it would undermine the good standing of systematic theorizing about the propositional attitu…Read more
  •  264
    Classical Opacity
    Philosophy and Phenomenological Research 101 (3): 524-566. 2020.
    Philosophy and Phenomenological Research, EarlyView.
  •  148
    Inexact Knowledge without Improbable Knowing
    Inquiry: An Interdisciplinary Journal of Philosophy 56 (1): 30-53. 2013.
    In a series of recent papers, Timothy Williamson has argued for the surprising conclusion that there are cases in which you know a proposition in spite of its being overwhelmingly improbable given what you know that you know it. His argument relies on certain formal models of our imprecise knowledge of the values of perceptible and measurable magnitudes. This paper suggests an alternative class of models that do not predict this sort of improbable knowing. I show that such models are motivated b…Read more
  •  314
    Agglomerative Algebras
    Journal of Philosophical Logic 48 (4): 631-648. 2018.
    This paper investigates a generalization of Boolean algebras which I call agglomerative algebras. It also outlines two conceptions of propositions according to which they form an agglomerative algebra but not a Boolean algebra with respect to conjunction and negation.
  •  799
    Diamonds are Forever
    with Cian Dorr
    Noûs 54 (3): 632-665. 2020.
    We defend the thesis that every necessarily true proposition is always true. Since not every proposition that is always true is necessarily true, our thesis is at odds with theories of modality and time, such as those of Kit Fine and David Kaplan, which posit a fundamental symmetry between modal and tense operators. According to such theories, just as it is a contingent matter what is true at a given time, it is likewise a temporary matter what is true at a given possible world; so a propositi…Read more
  •  250
    Conditional excluded middle (CEM) is the following principe of counterfactual logic: either, if it were the case that φ, it would be the case that ψ, or, if it were the case that φ, it would be the case that not-ψ. I will first show that CEM entails the identity of indiscernibles, the falsity of physicalism, and the failure of the modal to supervene on the categorical and of the vague to supervene on the precise. I will then argue that we should accept these startling conclusions, since CEM is v…Read more
  •  50
    Counterfactuals and Propositional Contingentism
    Review of Symbolic Logic 10 (3): 509-529. 2017.
    This article explores the connection between two theses: the principle of conditional excluded middle for the counterfactual conditional, and the claim that it is a contingent matter which (coarse grained) propositions there are. Both theses enjoy wide support, and have been defended at length by Robert Stalnaker. We will argue that, given plausible background assumptions, these two principles are incompatible, provided that conditional excluded middle is understood in a certain modalized way. W…Read more
  •  410
    Counting Incompossibles
    Mind 126 (504). 2017.
    We often speak as if there are merely possible people—for example, when we make such claims as that most possible people are never going to be born. Yet most metaphysicians deny that anything is both possibly a person and never born. Since our unreflective talk of merely possible people serves to draw non-trivial distinctions, these metaphysicians owe us some paraphrase by which we can draw those distinctions without committing ourselves to there being merely possible people. We show that such p…Read more
  •  162
    Knowledge, counterfactuals, and determinism
    Philosophical Studies 172 (9): 2275-2278. 2015.
    Deterministic physical theories are not beyond the reach of scientific discovery. From this fact I show that David Lewis was mistaken to think that small counterfactual perturbations from deterministic worlds involve violations of those world’s laws
  •  261
    Reality is not structured
    Analysis 77 (1). 2017.
    The identity predicate can be defined using second-order quantification: a=b =df ∀F(Fa↔Fb). Less familiarly, a dyadic sentential operator analogous to the identity predicate can be defined using third-order quantification: ϕ≡ψ =df ∀X(Xϕ↔Xψ), where X is a variable of the same syntactic type as a monadic sentential operator. With this notion in view, it is natural to ask after general principles governing its application. More grandiosely, how fine-grained is reality? I will argue that reality is …Read more
  •  1240
    Knowing against the odds
    Philosophical Studies 170 (2): 277-287. 2014.
    We present and discuss a counterexample to the following plausible principle: if you know that a coin is fair, and for all you know it is going to be flipped, then for all you know it will land tails.
  •  190
    Taking a chance on KK
    Philosophical Studies 175 (1): 183-196. 2018.
    Dorr et al. present a case that poses a challenge for a number of plausible principles about knowledge and objective chance. Implicit in their discussion is an interesting new argument against KK, the principle that anyone who knows p is in a position to know that they know p. We bring out this argument, and investigate possible responses for defenders of KK, establishing new connections between KK and various knowledge-chance principles.
  •  165
    An Argument For Necessitism
    Philosophical Perspectives 30 (1): 160-182. 2016.
    This paper presents a new argument for necessitism, the claim that necessarily everything is necessarily something. The argument appeals to principles about the metaphysics of quantification and predication which are best seen as constraints on reality’s fineness of grain. I give this argument in section 4; the impatient reader may skip directly there. Sections 1-3 set the stage by surveying three other arguments for necessitism. I argue that none of them are persuasive, but I think it is illumi…Read more
  •  119
    Williamson on necessitism
    Canadian Journal of Philosophy 46 (4-5): 613-639. 2016.
    I critically discuss some of the main arguments of Modal Logic as Metaphysics, present a different way of thinking about the issues raised by those arguments, and briefly discuss some broader issues about the role of higher-order logic in metaphysics.