•  1141
    On counterpossibles
    Philosophical Studies 168 (2): 327-353. 2013.
    The traditional Lewis–Stalnaker semantics treats all counterfactuals with an impossible antecedent as trivially or vacuously true. Many have regarded this as a serious defect of the semantics. For intuitively, it seems, counterfactuals with impossible antecedents—counterpossibles—can be non-trivially true and non-trivially false. Whereas the counterpossible "If Hobbes had squared the circle, then the mathematical community at the time would have been surprised" seems true, "If Hobbes had squared…Read more
  •  1132
    In this paper, I investigate whether we can use a world-involving framework to model the epistemic states of non-ideal agents. The standard possible-world framework falters in this respect because of a commitment to logical omniscience. A familiar attempt to overcome this problem centers around the use of impossible worlds where the truths of logic can be false. As we shall see, if we admit impossible worlds where “anything goes” in modal space, it is easy to model extremely non-ideal agents tha…Read more
  •  1009
    On the rationality of pluralistic ignorance
    with Jens Ulrik Hansen and Nikolaj Jang Lee Linding Pedersen
    Synthese 191 (11): 2445-2470. 2014.
    Pluralistic ignorance is a socio-psychological phenomenon that involves a systematic discrepancy between people’s private beliefs and public behavior in certain social contexts. Recently, pluralistic ignorance has gained increased attention in formal and social epistemology. But to get clear on what precisely a formal and social epistemological account of pluralistic ignorance should look like, we need answers to at least the following two questions: What exactly is the phenomenon of pluralistic…Read more
  •  858
    Hyperintensional semantics: a Fregean approach
    Synthese 197 (8): 3535-3558. 2020.
    In this paper, we present a new semantic framework designed to capture a distinctly cognitive or epistemic notion of meaning akin to Fregean senses. Traditional Carnapian intensions are too coarse-grained for this purpose: they fail to draw semantic distinctions between sentences that, from a Fregean perspective, differ in meaning. This has led some philosophers to introduce more fine-grained hyperintensions that allow us to draw semantic distinctions among co-intensional sentences. But the hype…Read more
  •  837
    Artificial Intelligence and Patient-Centered Decision-Making
    Philosophy and Technology 34 (2): 349-371. 2020.
    Advanced AI systems are rapidly making their way into medical research and practice, and, arguably, it is only a matter of time before they will surpass human practitioners in terms of accuracy, reliability, and knowledge. If this is true, practitioners will have a prima facie epistemic and professional obligation to align their medical verdicts with those of advanced AI systems. However, in light of their complexity, these AI systems will often function as black boxes: the details of their cont…Read more
  •  805
    Non-Ideal Epistemic Spaces
    Dissertation, Australian National University. 2010.
    In a possible world framework, an agent can be said to know a proposition just in case the proposition is true at all worlds that are epistemically possible for the agent. Roughly, a world is epistemically possible for an agent just in case the world is not ruled out by anything the agent knows. If a proposition is true at some epistemically possible world for an agent, the proposition is epistemically possible for the agent. If a proposition is true at all epistemically possible worlds for an a…Read more
  •  743
    Problems in Epistemic Space
    Journal of Philosophical Logic 43 (1): 153-170. 2012.
    When a proposition might be the case, for all an agent knows, we can say that the proposition is epistemically possible for the agent. In the standard possible worlds framework, we analyze modal claims using quantification over possible worlds. It is natural to expect that something similar can be done for modal claims involving epistemic possibility. The main aim of this paper is to investigate the prospects of constructing a space of worlds—epistemic space—that allows us to model what is epist…Read more
  •  521
    A Dynamic Solution to the Problem of Logical Omniscience
    Journal of Philosophical Logic 48 (3): 501-521. 2019.
    The traditional possible-worlds model of belief describes agents as ‘logically omniscient’ in the sense that they believe all logical consequences of what they believe, including all logical truths. This is widely considered a problem if we want to reason about the epistemic lives of non-ideal agents who—much like ordinary human beings—are logically competent, but not logically omniscient. A popular strategy for avoiding logical omniscience centers around the use of impossible worlds: worlds tha…Read more
  •  433
    Bayesianism for non-ideal agents
    Erkenntnis 1-23. forthcoming.
    Orthodox Bayesianism is a highly idealized theory of how we ought to live our epistemic lives. One of the most widely discussed idealizations is that of logical omniscience: the assumption that an agent’s degrees of belief must be probabilistically coherent to be rational. It is widely agreed that this assumption is problematic if we want to reason about bounded rationality, logical learning, or other aspects of non-ideal epistemic agency. Yet, we still lack a satisfying way to avoid logical omn…Read more
  •  388
    Granularity problems
    Philosophical Quarterly 67 (266): 22-37. 2017.
    Possible-worlds accounts of mental or linguistic content are often criticized for being too coarse-grained. To make room for more fine-grained distinctions among contents, several authors have recently proposed extending the space of possible worlds by "impossible worlds". We argue that this strategy comes with serious costs: we would effectively have to abandon most of the features that make the possible-worlds framework attractive. More generally, we argue that while there are intuitive and th…Read more
  •  369
    New Essays on the Knowability Paradox
    History and Philosophy of Logic 33 (1). 2012.
    History and Philosophy of Logic, Volume 33, Issue 1, Page 101-104, February 2012
  •  257
    Higher-order knowledge and sensitivity
    with Jens Christian Bjerring and Lars Bo Gundersen
    Canadian Journal of Philosophy 50 (3): 339-349. 2020.
    It has recently been argued that a sensitivity theory of knowledge cannot account for intuitively appealing instances of higher-order knowledge. In this paper, we argue that it can once careful attention is paid to the methods or processes by which we typically form higher-order beliefs. We base our argument on what we take to be a well-motivated and commonsensical view on how higher-order knowledge is typically acquired, and we show how higher-order knowledge is possible in a sensitivity theory…Read more
  •  179
    While many philosophers have agreed that evidence of disagreement is a kind of higher-order evidence, this has not yet resulted in formally precise higher-order approaches to the problem of disagreement. In this paper, we outline a simple formal framework for determining the epistemic significance of a body of higher-order evidence, and use this framework to motivate a novel interpretation of the popular “equal weight view” of peer disagreement—we call it the Variably Equal Weight View (VEW). We…Read more
  •  125
    In this paper we explore the potential bearing of the extended mind thesis—the thesis that the mind extends into the world—on epistemology. We do three things. First, we argue that the combination of the extended mind thesis and reliabilism about knowledge entails that ordinary subjects can easily come to enjoy various forms of restricted omniscience. Second, we discuss the conceptual foundations of the extended mind and knowledge debate. We suggest that the theses of extended mind and extended …Read more
  •  106
    Extended knowledge overextended?
    In Extending knowledge: reflections on epistemic agency and epistemic environment in East-West philosophy, Palgrave Macmillan. forthcoming.