Brian Weatherson

This paper presents a new theory of the truth conditions for indicative conditionals. The theory allows us to give a fairly unified account of the semantics for indicative and subjunctive conditionals, though there remains a distinction between the two classes. Put simply, the idea behind the theory is that the distinction between the indicative and the subjunctive parallels the distinction between the necessary and the a priori. Since that distinction is best understood formally using the resources of two-dimensional modal logic, those resources will be brought to bear on the logic of conditionals.

The Sleeping Beauty puzzle provides a nice illustration of the approach to self-locating belief defended by Robert Stalnaker in Our Knowledge of the Internal World (Stalnaker, 2008), as well as a test of the utility of that method. The setup of the Sleeping Beauty puzzle is by now fairly familiar. On Sunday Sleeping Beauty is told the rules of the game, and a (known to be) fair coin is flipped. On Monday, Sleeping Beauty is woken, and then put back to sleep. If, and only if, the coin landed tails, she is woken again on Tuesday after having her memory of the Monday awakening erased.1 On Wednesday she is woken again and the game ends. There are a few questions we can ask about Beauty’s attitudes as the game progresses. We’d like to know what her credence that the coin landed heads should be (a) Before she goes to sleep Sunday; (b) When she wakes on Monday; (c) When she wakes on Tuesday; and (d) When she wakes on Wednesday? Standard treatments of the Sleeping Beauty puzzle ignore (d), run together (b) and (c) into one (somewhat ill-formed) question, and then divide theorists into ‘halfers’ or ‘thirders’ depending on how they answer it. Following Stalnaker, I’m going to focus on (b) here, though I’ll have a little to say about (c) and (d) as well. I’ll be following orthodoxy in taking 1 2 to be the clear answer to (a), and in taking the correct answers to (b) and (c) to be independent of how the coin lands, though I’ll briefly question that assumption at the end. An answer to these four questions should respect two different kinds of constraints. The answer for day n should make sense ‘statically’. It should be a sensible answer to the question of what Beauty should do given what information she then has. And the answer should make sense ‘dynamically’. It should be a sensible answer to the question of how Beauty should have updated her credences from some earlier day, given rational credences on the earlier day. As has been fairly clear since the discussion of the problem in Elga (2000), Sleeping Beauty is puzzling because static and dynamic considerations appear to push in different directions..

Most people who believe in temporal parts believe that the referents of our ordinary referring terms, like Bill Clinton, or that table, are fusions of temporal parts from past, present and future times. Call these fusions worms, and the theory that the referents of ordinary referring terms (ordinary objects) the worm theory. Buying the metaphysical theory of temporal parts does not immediately imply that we must buy the worm theory. Theodore Sider (1996, 2000), for example, has suggested that these ordinary referring terms just pick out a single, instantaneous, temporal part. Sider’s theory, called the stage theory, solves some pressing philosophical problems, including the problem of temporary intrinsics. But the stage theory has several difficulties of its own, especially what I will call the problem of long-term intrinsics. I argue for a rival theory, the growing individuals theory. On this theory, the referents of our ordinary referring terms have past and present temporal parts, but not future temporal parts. This theory best accounts for our intuitions about which intrinsic properties ordinary objects have.

David Lewis (1941–2001) was one of the most important philosophers of the 20th Century. He made significant contributions to philosophy of language, philosophy of mathematics, philosophy of science, decision theory, epistemology, meta-ethics and aesthetics. In most of these fields he is essential reading; in many of them he is among the most important figures of recent decades. And this list leaves out his two most significant contributions. In philosophy of mind, Lewis developed and defended at length a new version of materialism (see the entry on physicalism). He started by showing how the motivations driving the identity theory of mind and functionalism could be reconciled in his theory of mind. He called this an identity theory, though his theory motivated the position now known as analytic functionalism. And he developed detailed accounts of mental content (building on Davidson’s interpretationism) and phenomenal knowledge (building on Nemirow’s ability hypothesis) that are consistent with his materialism. The synthesis Lewis ended up with is one of the central positions in contemporary debates in philosophy of mind. But his largest contributions were in metaphysics. One branch of his metaphysics was his Hume-inspired reductionism about the nomological. He developed a position he called “Humean supervenience”, the theory that said that there was nothing to reality except the spatio-temporal distribution of local natural properties. And he did this by showing in detail how laws, chances, counterfactual dependence, causation, dispositions and colours could be located within this Humean mosaic. The other branch of his metaphysics was his modal realism. Lewis held that the best theory of modality posited concrete possible worlds. A proposition is possible if and only if it is true at one of these worlds. Lewis defended this view in his most significant book, On the Plurality of Worlds. Alongside this, Lewis developed a new account of how to think about modal properties of individuals, namely counterpart theory, and showed how this theory resolved several long-standing puzzles about modal properties.

Ernest Adams has claimed that a probabilistic account of validity gives the best account of our intuitive judgements about the validity of arguments. In particular, he claims, it has the best hope of accounting for our judgements about many arguments involving conditionals. Most of the examples in the literature on this topic have been arguments framed in the language of propositional logic. I show that once we consider arguments involving predicates and involving identity, Adams’s strategy is less successful

In “Now the French are invading England” (Analysis 62, 2002, pp. 34-41), Komarine Romdenh-Romluc offers a new theory of the relationship between recorded indexicals and their content. Romdenh-Romluc’s proposes that Kaplan’s basic idea, that reference is determined by applying a rule to a context, is correct, but we have to be careful about what the context is, since it is not always the context of utterance. A few well known examples illustrate this. The “here” and “now” in “I am not here now” on an answering machine do not refer to the time and place of the original utterance, but to the time the message is played back, and the place its attached telephone is located. Any occurrence of “today” in a newspaper or magazine refers not to the day the story in which it appears was written, nor to the day the newspaper or magazine was printed, but to the cover date of that publication. Still, it is plausible that for each (token of an) indexical there is a salient context, and that “today” refers to the day of its context, “here” to the place of its context, and soon. Romdenh-Romluc takes this to be true, and then makes a proposal about what the salient context is. It is “the context that Ac would identify on the basis of cues that she would reasonably take U to be exploiting.” (39) Ac is the relevant audience, “the individual who it is reasonable to take the speaker to be addressing”, and who is assumed to be linguistically competent and attentive. (So Ac might not be the person U intends to address. This will not matter for what follows.) The proposal seems to suggest that it is impossible to trick a reasonably attentive hearer about what the referent of a particular indexical is. Since such trickery does seem possible, Romdenh-Romluc’s theory needs (at least) supplementation. I present two examples of such tricks.