In this paper we discuss how Causal Decision Theory should be modified to handle a class of problematic cases involving deterministic laws. Causal Decision Theory, as it stands, is problematically biased against your endorsing deterministic propositions (for example it tells you to deny Newtonian physics, regardless of how confident you are of its truth). Our response is that this is not a problem for Causal Decision Theory per se, but arises because of the standard method for assessing the truth of (...) certain counterfactuals. The truth of deterministic laws is `modally fragile' on the standard semantics for counterfactuals: if determinism is true and you were to do otherwise, the laws would be different. We provide two ways of avoiding this problem: 1) supplement the standard semantics for counterfactuals with impossible worlds, or 2) introduce rigid designators into the description of problematic decision situations. We argue that both of these approaches are well-motivated and can be readily incorporated into Lewisian Causal Decision Theory. (shrink)

No existing normative decision theory adequately handles risk. Expected Utility Theory is overly restrictive in prohibiting a range of reasonable preferences. And theories designed to accommodate such preferences (for example, Buchak's (2013) Risk‐Weighted Expected Utility Theory) violate the Betweenness axiom, which requires that you are indifferent to randomizing over two options between which you are already indifferent. Betweenness has been overlooked by philosophers, and we argue that it is a compelling normative constraint. Furthermore, neither Expected nor Risk‐Weighted Expected Utility Theory (...) allow for stakes‐sensitive risk‐attitudes—they require that risk matters in the same way whether you are gambling for loose change or millions of dollars. We provide a novel normative interpretation of Weighted‐Linear Utility Theory that solves all of these problems. (shrink)

Rational agents face choices, even when taking seriously the possibility of determinism. Rational agents also follow the advice of Causal Decision Theory (CDT). Although many take these claims to be well-motivated, there is growing pressure to reject one of them, as CDT seems to go badly wrong in some deterministic cases. We argue that deterministic cases do not undermine a counterfactual model of rational deliberation, which is characteristic of CDT. Rather, they force us to distinguish between counterfactuals that are relevant (...) and ones that are irrelevant for the purposes of deliberation. We incorporate this distinction into decision theory to develop ‘Selective Causal Decision Theory’, which delivers the correct recommendations in deterministic cases while respecting the key motivations behind CDT. (shrink)

Philosophers have spent a great deal of time debating whether intransitive preferences can be rational. I present a risky decision that poses a challenge for the defender of intransitivity. The defender of intransitivity faces a trilemma and must either: (i) reject the rationality of intransitive preferences, (ii) deny State-wise Dominance, or (iii) accept the bizarre verdict that you can be required to pay to relabel the tickets of a fair lottery. If we take the first horn, then we have a (...) synchronic refutation of intransitivity, an improvement on widely criticized diachronic arguments. I sketch possible responses that may rescue intransitivity and argue that each response is possible but generates an explanatory debt. I conclude by showing how the challenge here clarifies the foundations of decision theory without transitivity, conditional on some explanatory debt being payable. (shrink)

Until recently, many philosophers took Causal Decision Theory to be more successful than its rival, Evidential Decision Theory. Things have changed, however, with a renewed concern that cases involving an extreme form of decision instability are counterexamples to CDT :392–403, 1984; Egan in Philos Rev 116:93–114, 2007). Most prominent among those cases of extreme decision instability is the Psychopath Button, due to Andy Egan; in that case, CDT recommends a seemingly absurd act that almost certainly results in your death. This (...) renewed attention to decision instability has spurned an array of modifications to and rejections of CDT. I argue, however, that the Psychopath Button and its ilk are no counterexamples to CDT. That is, given the causalist’s commitments in Newcomb Problems, they already have the tools to justify CDT’s verdict in Egan-style cases of extreme decision instability. I first argue that there is no reason to think the Psychopath Button is a counterexample to CDT; in particular, many philosophers have placed too much weight on pre-theoretic intuition in Egan-cases, and apart from pre-theoretic intuition, arguments against CDT in cases of extreme decision instability are flawed. My second claim is that the causalist can provide good reasons for following CDT in cases of extreme decision instability. I present a new case, the Two Button Defense, that highlights precisely why the causalist can reasonably follow CDT in even the Psychopath Button. CDT therefore stands as a viable decision theory, without need for modification, restriction, or rejection. (shrink)

Review of Richard Bradley's Decision Theory with a Human Face.

When I take off my glasses, the world looks blurred. When I put them back on, it looks sharpedged. I do not think that the world really was blurred; I know that what changed was my relation to the distant physical objects ahead, not those objects themselves. I am more inclined to believe that the world really is and was sharp-edged. Is that belief any more reasonable than the belief that the world really is and was blurred? I see more (...) accurately with my glasses on than off, so visual appearances when they are on have some cognitive priority over visual appearances when they are off. If I must choose which kind of visual appearance to take at face value, I will choose the sharp-edged look. But what should I think when I see a mist, which looks very blurred however well I am seeing? Indeed, why choose to take any of the looks at face value? Why not regard all the choices as illegitimate projections of ways of seeing the world onto the world itself? (shrink)

Two opposing tendencies in the philosophy of language go by the names of ‘referentialism’ and ‘inferentialism’ respectively. In the crudest version of the contrast, the referentialist account of meaning gives centre stage to the referential semantics for a language, which is then used to explain the inference rules for the language, perhaps as those which preserve truth on that semantics (since a referential semantics for a language determines the truth-conditions of its sentences). By contrast, the inferentialist account of meaning gives (...) centre stage to the inference rules for the language, which are then used to explain its referential semantics, perhaps as the semantics on which the rules preserve truth. On pain of circularity, we cannot combine both directions of explanation. (shrink)

Metaphysical modalities are definable from counterfactual conditionals, and the epistemology of the former is a special case of the epistemology of the latter. In particular, the role of conceivability and inconceivability in assessing claims of possibility and impossibility can be explained as a special case of the pervasive role of the imagination in assessing counterfactual conditionals, an account of which is sketched. Thus scepticism about metaphysical modality entails a more far-reaching scepticism about counterfactuals. The account is used to question the (...) significance of the distinction between a priori and a posteriori knowledge. (shrink)

Knowledge and its Limits presents a systematic new conception of knowledge as a kind of mental stage sensitive to the knower's environment. It makes a major contribution to the debate between externalist and internalist philosophies of mind, and breaks radically with the epistemological tradition of analyzing knowledge in terms of true belief. The theory casts new light on such philosophical problems as scepticism, evidence, probability and assertion, realism and anti-realism, and the limits of what can be known. The arguments are (...) illustrated by rigorous models based on epistemic logic and probability theory. The result is a new way of doing epistemology and a notable contribution to the philosophy of mind. (shrink)

The book records a series of philosophical exchanges between its authors, amounting to a debate extended over more than fifteen years. Its subject matter is the nature and scope of reason. A central case at issue is basic logical knowledge, and the justification for basic deductive inferences, but the arguments range far more widely, at stake the distinctions between analytic and synthetic, and between a priori and a posteriori. The discussion naturally involves problems about the conditions for linguistic understanding and (...) competence, and what it might be to grasp a concept or to have an intuition. Since reason is central to philosophical method, there are associated implications for how philosophy itself works, or should work. In particular, the discussion raises fundamental concerns about how to approach epistemology. -/- . (shrink)

This chapter aims to attempt no more than to make some informal and unsystematic remarks on the transformation of analytic philosophy. It deals with a few sketchy remarks on the historiography of recent analytic philosophy. Writing in 1981, David Lewis described “a reasonable goal for a philosopher” as bringing one’s opinions into stable equilibrium. A natural comparison is between Lewis’s Quinean or at least post‐Quinean methodology and the methodology of Peter Strawson, Quine’s leading opponent from the tradition of ordinary language (...) philosophy. Analytic epistemology provides a good case study of the philosophical application of Gricean pragmatics outside the philosophy of language. On Michael Dummett picture of the history of philosophy, Descartes had made epistemology first philosophy, the engine for the rest of philosophy, and then Frege had replaced epistemology by the philosophy of language as first philosophy. The chapter suggests that philosophy sometimes already uses an abductive methodology and ought to use it more in the future. (shrink)

The second volume in the _Blackwell Brown Lectures in Philosophy_, this volume offers an original and provocative take on the nature and methodology of philosophy. Based on public lectures at Brown University, given by the pre-eminent philosopher, Timothy Williamson Rejects the ideology of the 'linguistic turn', the most distinctive trend of 20th century philosophy Explains the method of philosophy as a development from non-philosophical ways of thinking Suggests new ways of understanding what contemporary and past philosophers are doing.

Timothy Williamson gives an original and provocative treatment of deep metaphysical questions about existence, contingency, and change, using the latest resources of quantified modal logic. Contrary to the widespread assumption that logic and metaphysics are disjoint, he argues that modal logic provides a structural core for metaphysics.

Lemmon and Scott introduced the notion of a modal system's providing the rule of disjunction. No consistent normal extension of KB provides this rule. An alternative rule is defined, which KDB, KTB, and other systems are shown to provide, while K and other systems provide the Lemmon-Scott rule but not the alternative rule. If S provides the alternative rule then either —A is a theorem of S or A is whenever A -> ΠA is a theorem; the converse fails. It (...) is suggested that systems with this property are appropriate for handling sorites paradoxes, where D is read as 'clearly*. The S4 axiom fails in such systems. (shrink)

Vagueness provides the first comprehensive examination of a topic of increasing importance in metaphysics and the philosophy of logic and language. Timothy Williamson traces the history of this philosophical problem from discussions of the heap paradox in classical Greece to modern formal approaches such as fuzzy logic. He illustrates the problems with views which have taken the position that standard logic and formal semantics do not apply to vague language, and defends the controversial realistic view that vagueness is (...) a kind of ignorance--that there really is a grain of sand whose removal turns a heap into a non-heap, but we cannot know which one it is. (shrink)

Epistemic logics for subjects of bounded rationality are in effect nonnormal modal logics. Admissible rules are of interest in such logics. However, the usual methods for establishing admissibility employ Kripke models and are therefore inappropriate for nonnormal logics. This paper extends syntactic methods for a variety of rules and nonnormal logics. In doing so it answers a question asked by Chellas and Segerberg.

A concept of informational equivalence between relations is explicated to generalize some suggestions by Geach. It is shown that two relations are informationally equivalent if and only if each can be defined in terms of the other without the use of quantifiers. It is shown that there is a general method for listing the ./-place relations informationally equivalent to an arbitrary given /-place relation if and only if i (...) the invariants of the group of invertible quantifier-free definitions, for / =j. Quantifier-free definition is contrasted with general first-order definition by means of an example of two first-order interdefinable relations which are not interdefined by any pair of mutually inverse first-order definitions. (shrink)

Prevailing theories of the neural basis of at least a subset of individuals with autism spectrum disorder include an imbalance of excitatory and inhibitory neurotransmission. These circuitry imbalances are commonly probed in adults using auditory steady-state responses to elicit coherent electrophysiological responses from intact circuitry. Challenges to the ASSR methodology occur during development, where the optimal ASSR driving frequency may be unknown. An alternative approach is the amplitude-modulated sweep in which the amplitude of a tone is modulated as a sweep (...) from 10 to 100 Hz over the course of ∼15 s. Phase synchrony of evoked responses, measured via intra-trial coherence, is recorded as a function of frequency. We applied such AM sweep stimuli bilaterally to 40 typically developing and 80 children with ASD, aged 6–18 years. Diagnoses were confirmed by DSM-5 criteria as well as autism diagnostic observation schedule observational assessment. Stimuli were presented binaurally during MEG recording and consisted of 20 AM swept stimuli with a duration of ∼30 s each. Peak intra-trial coherence values and peak response frequencies of source modeled responses were examined. First, the phase synchrony or inter-trial coherence of the ASSR is diminished in ASD; second, hemispheric bias in the ASSR, observed in typical development, is maintained in ASD, and third, that the frequency at which the peak response is obtained varies on an individual basis, in part dependent on age, and with altered developmental trajectories in ASD vs. TD. Finally, there appears an association between auditory steady-state phase synchrony and clinical assessment of language ability/impairment. We concluded that the AM sweep stimulus provides a mechanism for probing ASSR in an unbiased fashion, during developmental maturation of peak response frequency, peak frequencies vary, in part due to developmental age, and importantly, ITC at this peak frequency is diminished in ASD, with the degree of ITC disturbance related to clinically assessed language impairment. (shrink)

This paper is concerned with formal solutions to the lottery paradox on which high probability defeasibly warrants acceptance. It considers some recently proposed solutions of this type and presents an argument showing that these solutions are trivial in that they boil down to the claim that perfect probability is sufficient for rational acceptability. The argument is then generalized, showing that a broad class of similar solutions faces the same problem. An argument against some formal solutions to the lottery paradox The (...) argument generalized Some variations Adding modalities Anticipated objections. (shrink)

What does 'if' mean? Timothy Williamson presents a controversial new approach to understanding conditional thinking, which is central to human cognitive life. He argues that in using 'if' we rely on psychological heuristics, fast and frugal methods which can lead us to trust faulty data and prematurely reject simple theories.

This paper explains and defends the idea that metaphysical necessity is the strongest kind of objective necessity. Plausible closure conditions on the family of objective modalities are shown to entail that the logic of metaphysical necessity is S5. Evidence is provided that some objective modalities are studied in the natural sciences. In particular, the modal assumptions implicit in physical applications of dynamical systems theory are made explicit by using such systems to define models of a modal temporal logic. Those assumptions (...) arguably include some necessitist principles. -/- Too often, philosophers have discussed ‘metaphysical’ modality — possibility, contingency, necessity — in isolation. Yet metaphysical modality is just a special case of a broad range of modalities, which we may call ‘objective’ by contrast with epistemic and doxastic modalities, and indeed deontic and teleological ones (compare the distinction between objective probabilities and epistemic or subjective probabilities). Thus metaphysical possibility, physical possibility and immediate practical possibility are all types of objective possibility. We should study the metaphysics and epistemology of metaphysical modality as part of a broader study of the metaphysics and epistemology of the objective modalities, on pain of radical misunderstanding. Since objective modalities are in general open to, and receive, natural scientific investigation, we should not treat the metaphysics and epistemology of metaphysical modality in isolation from the metaphysics and epistemology of the natural sciences. -/- In what follows, Section 1 gives a preliminary sketch of metaphysical modality and its place in the general category of objective modality. Section 2 reviews some familiar forms of scepticism about metaphysical modality in that light. Later sections explore a few of the many ways in which natural science deals with questions of objective modality, including questions of quantified modal logic. (shrink)

_Identity and Discrimination_, originally published in 1990 and the first book by respected philosopher Timothy Williamson, is now reissued and updated with the inclusion of significant new material. Williamson here proposes an original and rigorous theory linking identity, a relation central to metaphysics, and indiscriminability, a relation central to epistemology.__ Updated and reissued edition of Williamson’s first publication, with the inclusion of significant new material Argues for an original cognitive account of the relation between identity and (...) discrimination that has been influential in the philosophy of perception Pioneers the use of epistemic logic to solve puzzles about indiscriminability Develops the application of techniques from mathematical logic to understand issues about identity over time and across possible worlds. (shrink)

Many philosophers, following David Lewis, believe that we should look to counterpart theory, not quantified modal logic, as a means of understanding modal discourse. We argue that this is a mistake. Significant parts of modal discourse involve either implicit or explicit reference to what is actually the case, raising the question of how talk about actuality is to be represented counterpart-theoretically. By considering possible modifications of Lewis's counterpart theory, including actual modifications due to Graeme Forbes and Murali Ramachandran, we argue (...) that no coherent version of counterpart theory can provide a plausible representation of talk about actuality, and so, we conclude, counterpart theory should be rejected. (shrink)

This study reassesses the concept of the Anthropocene as a new geological age as it is influencing contemporary debates in social theory. As a unit of geological time whose changes are allegedly caused, directly and indirectly, by human beings, this scientific concept challenges the existing constructions of theoretical binaries, such as nature/culture, environment/society, objectivity/subjectivity or happenstance/design, in social theory. The analysis suggests many understandings of the Anthropocene in social theory are politicized over-interpretations of natural events, and these moves appear to (...) be developing moral rhetorics of, and operational plans for, managing the Anthropocene to create specific outcomes for those who are the managers as well as the managed. The fact that human beings do not, in fact, have this measure of technical control is ignored by advocates of Anthropocenarian politics to advance their policy agendas. (shrink)

This paper aims to identify the constitutive rule of assertion, conceived by analogy with the rules of a game. That assertion has such rules is by no means obvious; perhaps it is more like a natural phenomenon than it seems. One way to find out is by supposing that it has such rules, in order to see where the hypothesis leads and what it explains. That will be done here. The hypothesis is not perfectly clear, of course, but we have (...) at least a crude conception of constitutive rules, which we may refine as we elaborate the hypothesis. Although no attempt will be made here to define ‘rule’, some remarks on constitutive rules will focus the discussion. (shrink)

In the current dialogue between two authors with different views on analysis, philosophy, and the use of labels, the leading question is: How should one understand the expression ‘analytic philosophy’? Lewin argues that as there are no generally agreed tenets and methods of what is being called ‘analytic philosophy’, the name is to be replaced by a more specific one or abandoned. Williamson defends the use of this phrase, claiming that it is quite serviceable, as it relates to a (...) broad tradition of influence, while it is not even required to adhere to the method of analysis in any distinctive sense. Lewin counters that, in this case, ‘analytic philosophy’ is too empty. One could heal this by conceptual analysis of ‘analytic philosophy’ — but then Kant, for whom philosophy is inherently analytic, would be a proponent of analytic philosophy. Another option is to follow Ryle’s ideal of a label-free, coherent and honest thinking. As Lewin argues, Williamson’s views seem at least partially to agree with Kant’s conception of the difference between philosophy and history of philosophy as well as empirical analysis and the underlying empirical realism. Williamson replies that he uses ‘analytic philosophy’ in its current meaning, which is not composed of the meanings of ‘analytic’ and ‘philosophy’. The current use is different from the earlier ones and not applicable to Kant. He argues against the transcendental idealism and the coarse-grained distinction between analytic and synthetic and a priori and a posteriori that requires an update. (shrink)

Improbable knowing is knowing something even though it is almost certain on one’s evidence at the time that one does not know that thing. Once probabilities on the agent’s evidence are introduced into epistemic logic in a very natural way, it is easy to construct models of improbable knowing, some of which have realistic interpretations, for instance concerning agents like us with limited powers of perceptual discrimination. Improbable knowing is an extreme case of failure of the KK principle, that is, (...) of a case of knowing something even though one does not know at the time that one knows that thing. A generalization of the argument yields cases of improbable rationality, in which it is rational for one to do something even though it is almost certain on one’s evidence at the time that it is not rational for one to do that thing. When the models are elaborated to represent appearances and beliefs as well as knowledge, they turn out to contain Gettier cases. Neglect of the possibility of improbable knowing may cause some sceptical claims and claims of the non-closure of knowledge under competent deduction to look more plausible than they deserve to. A formal appendix explores the closely related question of the conditions under which a reflection principle is violated. The principle says that the evidential probability of a proposition conditional on the evidential probability of that proposition’s being c is itself c. (shrink)

On reading the last sentence, did you interpret me as saying falsely that everything — everything in the entire universe — was packed into my carry-on baggage? Probably not. In ordinary language, ‘everything’ and other quantifiers (‘something’, ‘nothing’, ‘every dog’, ...) often carry a tacit restriction to a domain of contextually relevant objects, such as the things that I need to take with me on my journey. Thus a sentence of the form ‘Everything Fs’ is true as uttered in a (...) context C if and only if everything that is relevant in C satisfies the predicate ‘F’; ‘everything’ ranges just over the contextually relevant things. Such generality is restricted in a context-relative way. (shrink)

Abstract: Some proponents of “experimental philosophy” criticize philosophers' use of thought experiments on the basis of evidence that the verdicts vary with truth-independent factors. However, their data concern the verdicts of philosophically untrained subjects. According to the expertise defence, what matters are the verdicts of trained philosophers, who are more likely to pay careful attention to the details of the scenario and track their relevance. In a recent article, Jonathan M. Weinberg and others reply to the expertise defence that there (...) is no evidence for such expertise. They now receive a reply in this article, which argues that they have misconstrued the dialectical situation. Since they have produced no evidence that philosophical training is less efficacious for thought experimentation than for other cognitive tasks for which they acknowledge that it produces genuine expertise, such as informal argumentation, they have produced no evidence for treating the former more sceptically than the latter. (shrink)