John Hawthorne

We explore the consequences of a natural and well‐motivated modeling assumption of Bayesian epistemology, according to which the objects of credence are sentences in the agent's language. We show that this assumption is inconsistent with two further natural Bayesian idealizations: those of Logical Perfection (the logical‐deductive consistency and closure of the sentences in which the agent is certain) and of perfect access to (i.e., certainty regarding) the presence or absence of certainty in any particular sentence in the agent's language—an assumption we call “Luminosity.” That is, it turns out that a luminous agent is an irrational agent. After presenting our main result and some related impossibility results concerning variations on Logical Perfection and Luminosity, we briefly examine the range of candidate solutions to the puzzles that these results present us with.

This paper presents an argument that certain AI safety measures, rather than mitigating existential risk, may instead exacerbate it. Under certain key assumptions - the inevitability of AI failure, the expected correlation between an AI system's power at the point of failure and the severity of the resulting harm, and the tendency of safety measures to enable AI systems to become more powerful before failing - safety efforts have negative expected utility. The paper examines three response strategies: Optimism, Mitigation, and Holism. Each faces challenges stemming from intrinsic features of the AI safety landscape that we term Bottlenecking, the Perfection Barrier, and Equilibrium Fluctuation. The surprising robustness of the argument forces a reexamination of core assumptions around AI safety and points to several avenues for further research.

The adjective ‘is justified’ has all the hallmarks of a gradable adjective. But the relationship between gradable uses and straightforward predications of the form ‘x is justified’ has been underexplored by epistemologists. In this paper we undertake to do some ground clearing as a prelude to better understanding this relationship. The adjective ‘is justified’ has all the hallmarks of a gradable adjective. But the relationship between gradable uses and straightforward predications of the form ‘x is justified’ has been underexplored by epistemologists. In this paper we undertake to do some ground clearing as a prelude to better understanding this relationship.

A very simple contextualist treatment of a sentence containing an epistemic modal, e.g. a might be F, is that it is true iff for all the contextually salient community knows, a is F. It is widely agreed that the simple theory will not work in some cases, but the counterexamples produced so far seem amenable to a more complicated contextualist theory. We argue, however, that no contextualist theory can capture the evaluations speakers naturally make of sentences containing epistemic modals. If we want to respect these evaluations, our best option is a relativist theory of epistemic modals. On a relativist theory, an utterance of a might be F can be true relative to one context of evaluation and false relative to another. We argue that such a theory does better than any rival approach at capturing all the behaviour of epistemic modals.

A very simple contextualist treatment of a sentence containing an epistemic modal, e.g. a might be F, is that it is true iff for all the contextually salient community knows, a is F. It is widely agreed that the simple theory will not work in some cases, but the counterexamples produced so far seem amenable to a more complicated contextualist theory. We argue, however, that no contextualist theory can capture the evaluations speakers naturally make of sentences containing epistemic modals. If we want to respect these evaluations, our best option is a relativist theory of epistemic modals. On a relativist theory, an utterance of a might be F can be true relative to one context of evaluation and false relative to another. We argue that such a theory does better than any rival approach at capturing all the behaviour of epistemic modals.

What ought one to do, epistemically speaking, when faced with a disagreement? Faced with this question, one naturally hopes for an answer that is principled, general, and intuitively satisfying. We want to argue that this is a vain hope. Our claim is that a satisfying answer will prove elusive because of non-transparency: that there is no condition such that we are always in a position to know whether it obtains. When we take seriously that there is nothing, including our own minds, to which we have assured access, the familiar project of formulating epistemic norms is destabilized. In this paper, we will show how this plays out in the special case of disagreement. But we believe that a larger lesson can ultimately be extracted from our discussion: namely, that non-transparency threatens our hope for fully satisfying epistemic norms in general.

The modality of normality distinguishes states of affairs which are normal from those which are abnormal. Existing work on the modality of normality assumes that it is a restriction of metaphysical modality. In this paper, we argue that this assumption is inappropriate and explore the consequences of abandoning it. After preliminary discussion (§1), we introduce the dominant framework for reasoning about normality (§2) and argue that it ascribes implausibly strong structural properties to the modality. In its place, we propose a new framework, which avoids this commitment (§§3-5). This account has a number of interesting features, which we explore in both an informal and formal setting. If correct, it implies that the modality of normality occupies a distinctive place in the space of modalities. Before concluding, we consider some of the wider implications of our account (§6), focusing on the role normality has played in epistemic theorizing.

This chapter examines sensitive moderate invariantism, and how it may help the puzzle. It describes two mechanisms that bear on the truth of knowledge claims; ones that are similar to contextualist machinery except that they are conceived of as making for subject-sensitivity. The sensitive moderate invariantist claims that the extension of ‘know’ depends not only on the kinds of actors traditionally adverted to accounts of knowledge but also on the kinds of factors that in the contextualist’s hands make for ascriber-dependence.

Increasingly, the mind is being treated as a fit subject for scientific inquiry. As cognitive science and empirical psychology strive to uncover the mind's secrets, it is fitting to inquire as to what distinctive role is left for philosophy in the study of mind. This collection, which includes contributions by some of the leading scholars in the field, offers a rich variety of perspectives on this issue. Topics addressed include: the place of a priori inquiry in philosophy of mind, moral psychology, consciousness, social dimensions of intentionality, the relation of logic to philosophical psychology, objectivity and the mind, and privileged access.

In the last few years there has been an explosion of philosophical interest in perception; after decades of neglect, it is now one of the most fertile areas for new work. Perceptual Experience presents new work by fifteen of the world's leading philosophers. All papers are written specially for this volume, and they cover a broad range of topics to do with sensation and representation, consciousness and awareness, and the connections between perception and knowledge and between perception and action. This will be the book on the philosophy of perception, a fascinating resource for philosophers and psychologists.

Mark Johnston (2016, 2017) has argued on ethical grounds against a wide variety of "naturalistic" world views, which imply that 'in our close vicinity, there are many persisting things all ontologically on a par, very similar in their features and such that they come into being and cease to exist at various times'—'personites', for short. Johnston argues that if personites exist, their intrinsic properties are compatible with their being people and thus having moral status; but since moral status is an intrinsic matter, this implies that personites enjoy the same kind of moral status as people, a conclusion which leads to various bizarre ethical consequences. In response, we defend the view that although personites exist, they lack moral status, and have intrinsic properties (including modal properties) which no person could have. We also isolate a different argument for the moral status of certain personites, based on the claim that they instantiate properties which 'person' could very easily have expressed; we show how this argument can be resisted by adopting a pluralistic semantics, on which predicates like 'person' and 'being with moral status' express many properties even at the actual world.

Since the release of ChatGPT, there has been a lot of debate about whether AI systems pose an existential risk to humanity. This paper develops a general framework for thinking about the existential risk of AI systems. We analyze a two-premise argument that AI systems pose a threat to humanity. Premise one: AI systems will become extremely powerful. Premise two: if AI systems become extremely powerful, they will destroy humanity. We use these two premises to construct a taxonomy of ‘survival stories’, in which humanity survives into the far future. In each survival story, one of the two premises fails. Either scientific barriers prevent AI systems from becoming extremely powerful; or humanity bans research into AI systems, thereby preventing them from becoming extremely powerful; or extremely powerful AI systems do not destroy humanity, because their goals prevent them from doing so; or extremely powerful AI systems do not destroy humanity, because we can reliably detect and disable systems that have the goal of doing so. We argue that different survival stories face different challenges. We also argue that different survival stories motivate different responses to the threats from AI. Finally, we use our taxonomy to produce rough estimates of ‘P(doom)’, the probability that humanity will be destroyed by AI.

The term ‘three-dimensionalism’ has wide currency in contemporary metaphysical debates, yet it is far from clear what the term means. Often three-dimensionalism is explained using metaphors: objects are wholly present at a time, rather than ‘stretched out’ across time and partially present at each. Since the ideology of ‘wholly present’ and ‘stretched out’ is too unclear to carry all the explanatory burden, there remains the task of explaining in a perspicuous way what exactly is at stake. This chapter distinguishes a number of issues that lie in the vicinity of the debates and indicate a range of considerations that may be brought to bear.

In an anonymous referee report written in 1945, Church suggested a sweeping argument against verificiationism, the thesis that every truth is knowable. The argument, which was published with due acknowledgement by Fitch almost two decades later, has generated significant attention as well as some interesting successor arguments. In this paper, we present the most important episodes in this intellectual history using the logic that Church himself favoured, and we give reasons for thinking that the arguments are less than decisive. However, we present some new arguments against verificationism that we believe to be dialectically effective.

Inquiry aims at knowledge. Your inquiry into a question succeeds just in case you come to know the answer. However, combined with a common picture on which misleading evidence can lead knowledge to be lost, this view threatens to recommend a novel form of dogmatism. At least in some cases, individuals who know the answer to a question appear required to avoid evidence bearing on it. In this paper, we’ll aim to do two things. First, we’ll present an argument for this novel form of dogmatism and show that it presents a substantive challenge. Second, we’ll consider a way those who take knowledge to be the aim of inquiry can mount a response. In the course of doing so, we’ll try to get clearer on the normative connections between inquiry, knowledge and evidence gathering.

This paper offers a new argument against the KK thesis, which says that if you know p, then you know that you know p. We argue that KK is inconsistent with the fact that anyone denies the KK thesis: imagine that Dudley says he knows p but that he does not have 100 iterations of knowledge about p. If KK were true, Dudley would know that he has 100 iterations of knowledge about p, and so he wouldn’t deny that he did. We consider several epicycles, and also explore whether the argument type also challenges other structural conditions on knowledge, such as closure under deduction.