• Evidential Decision Theory
    Cambridge University Press. 2021.
    Evidential Decision Theory is a radical theory of rational decision-making. It recommends that instead of thinking about what your decisions *cause*, you should think about what they *reveal*. This Element explains in simple terms why thinking in this way makes a big difference, and argues that doing so makes for *better* decisions. An appendix gives an intuitive explanation of the measure-theoretic foundations of Evidential Decision Theory.
  •  20
    Introducing Identity
    Journal of Philosophical Logic 1-21. forthcoming.
    The best-known syntactic account of the logical constants is inferentialism. Following Wittgenstein’s thought that meaning is use, inferentialists argue that meanings of expressions are given by introduction and elimination rules. This is especially plausible for the logical constants, where standard presentations divide inference rules in just this way. But not just any rules will do, as we’ve learnt from Prior’s famous example of tonk, and the usual extra constraint is harmony. Where does this…Read more
  •  96
    A decision problem where Causal Decision Theory (CDT) declines a free $1,000, with the foreseeable effect that the agent is $1,000 poorer, and in no other way better off, than if she had taken the offer.
  •  25
    Modern and Medieval Modal Spaces
    Aristotelian Society Supplementary Volume 94 (1): 255-273. 2020.
    The interesting question about modality is not about its extension, but about its point. Everyone can agree that the past is necessary in the Ockhamist sense but not in some ‘modern’ senses, and that the present is necessary in the Ockhamist sense but not in the Scotist sense. But why should it matter? These comments on Pasnau first set out a simple-minded explication in modern terms of some of these fourteenth-century ideas. Then I take issue with Pasnau’s claim that the necessity of the past h…Read more
  •  241
    Rationality and Future Discounting
    Topoi 39 (2): 245-256. 2018.
    The best justification of time-discounting is roughly that it is rational to care less about your more distant future because there is less of you around to have it. I argue that the standard version of this argument, which treats both psychological continuity and psychological connectedness as reasons to care about your future, can only rationalize an irrational—because exploitable—form of future discounting.
  •  173
    A choice function C is rational iff: if it allows a path through a sequence of decisions with a particular outcome, then that outcome is amongst the ones that C would have chosen from amongst all the possible outcomes of the sequence. This implies, and it is the strongest definition that implies, that anyone who is irrational could be talked out of their own preferences. It also implies weak but non-vacuous constraints on choices over ends. These do not include alpha or beta.
  •  49
    The paper discusses Ian Wells’s recent argument that there is a decision problem in which followers of Evidential Decision Theory end up poorer than followers of Causal Decision Theory despite having the same opportunities for money. It defends Evidential Decision Theory against Wells’s argument, on the following grounds. Wells's has not presented a decision problem in which his main claim is true. Four possible decision problems can be generated from his central example, in each of which follow…Read more
  •  100
    Objective Value Is Always Newcombizable
    Mind 129 (516): 1157-1192. 2020.
    This paper argues that evidential decision theory is incompatible with options having objective values. If options have objective values, then it should always be rationally permissible for an agent to choose an option if they are certain that the option uniquely maximizes objective value. But, as we show, if options have objective values and evidential decision theory is true, then it is not always rationally permissible for an agent to choose an option if they are certain that the option uniqu…Read more
  •  52
    Frankfurt cases and the Newcomb Problem
    Philosophical Studies 177 (11): 3391-3408. 2020.
    A standard argument for one-boxing in Newcomb’s Problem is ‘Why Ain’cha Rich?’, which emphasizes that one-boxers typically make a million dollars compared to the thousand dollars that two-boxers can expect. A standard reply is the ‘opportunity defence’: the two-boxers who made a thousand never had an opportunity to make more. The paper argues that the opportunity defence is unavailable to anyone who grants that in another case—a Frankfurt case—the agent is deprived of opportunities in the way th…Read more
  •  12
    Review of Lara Buchak, *Risk and Rationality* (review)
    British Journal for the Philosophy of Science Review of Books. 2016.
  •  141
    Abstract. Suppose that the word of an eyewitness makes it 80% probable that A committed a crime, and that B is drawn from a population in which the incidence rate of that crime is 80%. Many philosophers and legal theorists have held that if this is our only evidence against those parties then (i) we may be justified in finding against A but not against B; but (ii) that doing so incurs a loss in the accuracy of our findings. This paper argues against (ii). It argues that accuracy considerations c…Read more
  •  83
    Belief and religious ‘belief’
    Religious Studies 1-15. forthcoming.
    Is the analysis of religion best conducted in terms of the beliefs of its practitioners? I describe a Wittgenstein-inspired approach to belief on which it is dubious that religious practices satisfy the criteria for the attribution of belief. I defend this more moderate and plausible version of Needham's thesis against two natural reasons to think religious belief widespread.
  •  101
    The Meaning of Belief: Religion from an Atheist’s Point of View, by CraneTim. Cambridge, Mass.: Harvard University Press, 2017. Pp. xiv + 203.
  •  278
    Causal Decision Theory reckons the choice-worthiness of an option to be completely independent of its evidential bearing on its non-effects. But after one has made a choice this bearing is relevant to future decisions. Therefore it is possible to construct problems of sequential choice in which Causal Decision Theory makes a guaranteed loss. So Causal Decision Theory is wrong. The source of the problem is the idea that agents have a special perspective on their own contemplated actions, from whi…Read more
  •  245
    Review: John McDowell (review)
    Mind 115 (458): 403-409. 2006.
  •  7
    Newcomb's Problem (edited book)
    Cambridge University Press. 2018.
    Newcomb's Problem is a controversial paradox of decision theory. It is easily explained and easily understood, and there is a strong chance that most of us have actually faced it in some form or other. And yet it has proven as thorny and intractable a puzzle as much older and better-known philosophical problems of consciousness, scepticism and fatalism. It brings into very sharp and focused disagreement several long-standing philosophical theories on practical rationality, on the nature of free …Read more
  •  1
    Wittgenstein on seeing aspects
    In Hans-Johann Glock & John Hyman (eds.), A Companion to Wittgenstein, Blackwell. pp. 517-532. 2017.
    A resolution must give “seeing it differently” a sense that makes it clear that it is seeing that one is doing differently and not something else that is going on at the same time. The Berlin school of gestalt psychology took the view that alongside the colors and shapes traditionally thought to compose the visual field was a similarly perceptible aspect of “organization”. Wittgenstein considers the possibility of a physiological explanation of aspect change. This chapter details the Wittgenstei…Read more
  •  250
    Hume and the Independent Witnesses
    Mind 124 (496): 1013-1044. 2015.
    The Humean argument concerning miracles says that one should always think it more likely that anyone who testifies to a miracle is lying or deluded than that the alleged miracle actually occurred, and so should always reject any single report of it. A longstanding and widely accepted objection is that even if this is right, the concurring and non-collusive testimony of many witnesses should make it rational to believe in whatever miracle they all report. I argue that on the contrary, even multip…Read more
  •  490
    Causal Decision Theory and EPR correlations
    with Adam Caulton
    Synthese 191 (18): 4315-4352. 2014.
    The paper argues that on three out of eight possible hypotheses about the EPR experiment we can construct novel and realistic decision problems on which (a) Causal Decision Theory and Evidential Decision Theory conflict (b) Causal Decision Theory and the EPR statistics conflict. We infer that anyone who fully accepts any of these three hypotheses has strong reasons to reject Causal Decision Theory. Finally, we extend the original construction to show that anyone who gives any of the three hypoth…Read more
  •  114
    W. V. Quine
    In Cheryl Misak (ed.), The Oxford Handbook of American Philosophy, Oxford University Press. pp. 290-338. 2008.
    The paper summarizes the main points of Quine's epistemology and philosophy of language: empiricism, holism, semantic behaviourism, inscrutability of reference, indterminacy of translation and the rejection of analyticity.
  •  63
    Evidence, Decision and Causality
    Cambridge University Press. 2014.
    Most philosophers agree that causal knowledge is essential to decision-making: agents should choose from the available options those that probably cause the outcomes that they want. This book argues against this theory and in favour of evidential or Bayesian decision theory, which emphasises the symptomatic value of options over their causal role. It examines a variety of settings, including economic theory, quantum mechanics and philosophical thought-experiments, where causal knowledge seems to…Read more
  •  157
    Causation and Decision
    Proceedings of the Aristotelian Society 110 (2pt2): 111-131. 2010.
    Sophisticated ‘tickle’-style defences of Evidential Decision Theory take your motivational state to screen off your act from any state that is causally independent of it, thus ensuring that EDT and CDT converge. That leads to unacceptable instability in cases in which the correct action is obvious. We need a more liberal conception of what the agent controls. It follows that an ordinary deliberator should sometimes consider the past and not only the future to be subject to her present choice.
  •  98
    Saul Kripke
    Bloomsbury Academic. 2007.
    Saul Kripke is one of the most important and original post-war analytic philosophers. His work has undeniably had a profound impact on the philosophy of language and the philosophy of mind. Yet his ideas are amongst the most challenging frequently encountered by students of philosophy. In this informative and accessible book, Arif Ahmed provides a clear and thorough account of Kripke's philosophy, his major works and ideas, providing an ideal guide to the important and complex thought of this ke…Read more
  •  240
    The paper argues against Bob Hale's (1999) argument that enquirers must regard some truths as necessary truths. Hale's argument against Quinean skepticism. like many similar arguments due to McFetridge, Wright and others, involves a quantifier shift fallacy.
  •  26
    Deductive inference seems to reveal semantic connections between their premise(s) and conclusion that were there all along. This looks inconsistent with Wittgenstein's later views on meaning. The paper argues that W's treatment of aspects suggests a Wittgensteinian treatment of deduction that accommodates the troublesome phenomenon without conceding its force.
  •  304
    Arntzenius on ‘Why ain’cha rich?’
    with Huw Price
    Erkenntnis 77 (1): 15-30. 2012.
    The best-known argument for Evidential Decision Theory (EDT) is the ‘Why ain’cha rich?’ challenge to rival Causal Decision Theory (CDT). The basis for this challenge is that in Newcomb-like situations, acts that conform to EDT may be known in advance to have the better return than acts that conform to CDT. Frank Arntzenius has recently proposed an ingenious counter argument, based on an example in which, he claims, it is predictable in advance that acts that conform to EDT will do less well than…Read more
  •  211
    Push the Button
    Philosophy of Science 79 (3): 386-395. 2012.
    Opponents of Causal Decision Theory (CDT) sometimes claim (i) that it gives the wrong advice in Egan-style cases, where the CDT-endorsed act brings news that it causes a bad outcome; (ii) that CDT gives the right advice in Newcomb cases, where it is known in advance that the CDT-act causes you to be richer than the alternative. This paper argues that (i) and (ii) cannot both be true if rational preference over acts is transitive.