Arif Ahmed

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 followers of Evidential Decision Theory do at least as well as followers of Causal Decision Theory. There is another case in which followers of Causal Decision Theory have the same opportunities for making money but end up worse than followers of Evidential Decision Theory.

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 that advocates of Frankfurt cases typically claim.

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 make a practical difference. The arguments make novel use of machinery from other areas of philosophical inquiry, including first-person epistemology and the free will debate. The book also illustrates the applicability of decision theory itself to questions about the direction of time and the special epistemic status of agents.

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 leave identity? It’s usually taken as a logical constant but it doesn’t seem harmonious: standardly, the introduction rule only concerns a subset of the formulas canvassed by the elimination rule. In response, Read [5, 8] and Klev [3] amend the standard approach. We argue that both attempts fail, in part because of a misconception regarding inferentialism and identity that we aim to identify and clear up.

The interesting question about modality is not about its extension, but about its point. Everyone can agree (for instance) 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 (2020) first set out a simple-minded explication in modern terms of some of these fourteenth-century ideas. Then I take issue with (a) Pasnau’s claim that the necessity of the past has something to do with the structure of ‘narrative history’, and (b) Duns Scotus’s claim that the contingency of the present has something to do with human freedom.

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 Wittgenstein's account that it is worth making three general comments about what explaining a psychological concept involves, according to his later philosophy. It focuses on Wittgenstein's writings on sensory aspects and non-sensory aspects. Kant's proposal was that the intuition is of an a priori manifold; but perhaps what is more plausible is that the objects of synoptic vision are not themselves individuals but concepts.

The paper attempts a novel defense of the main claim of Wittgenstein's Private Language Argument, i.e. that 'inner' ostensive definition is impossible. Part 1 traces Wittgenstein's target to the idea that 'ostensive definition' is a mental act, an idea that makes it tempting to think that its objects might just as well be private as public. Part 2 discusses a recent interpretation and defence of Wittgenstein's position due to Stroud and McGinn. On their view, private ostensive definition establishes no pattern of use because it fails to specify the type of inner episode that is being ostended. But not explicitly specifying a type is harmless so long as the ostension in fact brings it about that the subject's usage is sensitive to it. Part 3 proposes a new argument. Private ostensive definition does sustain a pattern of use, but that use is semantically indeterminate: nothing in it (or in the subject's mind) settles which of two alternative schemes of reference applies. The conclusion discusses Wittgenstein's best-known remarks on the subject from the perspective of this new argument.