John MacFarlane

Patrick Todd argues for a modified Peircean view on which all future contingents are false. According to Todd, this is the only view that makes sense if we fully embrace an open future, rejecting the idea of actual future history. I argue that supervaluational accounts, on which future contingents are neither true nor false, are fully consistent with the metaphysics of an open future. I suggest that it is Todd's failure to distinguish semantic and postsemantic levels that leads him to suppose otherwise. I also show how one can resist Todd's argument (with Brian Rabern) that the conceptual possibility of omniscience requires us to reject Retro‐closure ().

Abstract“Absolutely nothing,” say the radical Bayesians. “Simplifying decisions,” say the moderates. “Providing premises in practical reasoning,” say the epistemologists. “Coordinating with others,” say I. It is hard to see how to construct an adequate theory of rational behavior without using a graded notion of belief, such as credence. But once we have credence, what role is left for belief? After surveying some answers to this question, I will explore the idea that belief is in a different line of work altogether. Its job is not to rationalize and explain an agent’s behavior, but to track what the agent would accept as a reason. Although some philosophers have seen the connection between belief and reasons, they have tended to see reasons as part of a theory of rational action. This locates belief in the rationalizing and explaining business, where it must vie with credence. In contrast, I argue that reasons play no essential role in an account of individual rationality; they are important because we need to coordinate with others. Credence and belief thus answer to separate needs.

"Philosophical logic" describes two distinct areas: the investigation of the fundamental concepts of logic, the formal investigation of alternatives and extensions to classical logic. The first is a philosophical discipline, concerned with notions like truth, propositions, necessity, logical consequence, vagueness, and reasoning. The second is a technical discipline, devoted to developing formal logical systems-modal logics, second-order logics, intuitionistic logics, relevance logics, logics of vagueness and conditionals-and proving things about them. Most texts in philosophical logic focus on one of these areas, but in this book John MacFarlane treats them together in an integrated way, showing how philosophical considerations motivate the technical projects, and how the constraints revealed by the technical projects illuminate the philosophical issues. Topics covered include quantifiers, modal logic, indicative conditionals, model-theoretic and proof-theoretic characterizations of logical consequence, intuitionistic logic, fundamental logical disagreement, relevance logic, the relation of logic and reasoning, and vagueness. Each chapter is organized around suggested readings and includes exercises. Key Features: An integrated treatment of the technical and philosophical issues comprising philosophical logic Written by a leading authority on logicism and logical form and a successful expositor and teacher Designed to serve students taking only one course in logic beyond the introductory level Provides tools and concepts necessary to understand work in many areas of analytic philosophy Includes exercises, suggested readings, and suggestions for further exploration in each chapter.

The central chapter of Burnyeat’s Map is organized like a commentary, moving through Metaphysics Ζ (and parts of Η) section by section. But unlike a commentary, it does not strive for comprehensiveness. Its aim is to describe the general lay of the land—what is being argued for where, in what way, and why— and so its exegesis is limited to Aristotle’s “signposts.” For example, every time Aristotle says “we must investigate” or “as we have seen,” Burnyeat asks “where?” As far as possible, he tries to construct his map on philological evidence, remaining neutral on many of the substantive issues that have defined readings of Ζ. The hope is that, map in hand, we can interpret Ζ’s notoriously obscure arguments with a better sense of their place in Aristotle’s overall project.

On Schiffer’s new view, propositions are easy to come by. Any that-clause can be counted on to express one. Thus, trivially, there are vague propositions, conditional propositions, moral and aesthetic propositions. And where propositions go, truth and falsity follow: barring paradoxical cases, Schiffer accepts instances of the schemata “the proposition that p is true iff p” and “the proposition that p is false iff not-p.” What isn’t easy to find, Schiffer thinks, is determinate truth. By the end of the book, we have heard that a huge number of the things we say or think are indeterminate in truth value: not just whether Schiffer’s book is long, but whether the property of being in pain is identical with any physical property, whether torturing children for fun is morally permissible, whether modus ponens is a valid inference rule, and whether someone else would have shot Kennedy if Oswald hadn’t. Indeed, on Schiffer’s view, there are no determinately true moral propositions and virtually no determinately true conditionals that are “likely to interest us”.

This lecture presents my own solution to the problem posed in Lecture I. Instead of a new theory of speech acts, it offers a new theory of the contents expressed by vague assertions, along the lines of the plan expressivism Allan Gibbard has advocated for normative language. On this view, the mental states we express in uttering vague sentences have a dual direction of fit: they jointly constrain the doxastic possibilities we recognize and our practical plans about how to draw boundaries. With this story in hand, I reconsider some of the traditional topics connected with vagueness: bivalence, the sorites paradox, higher-order vagueness, and the nature of vague thought. I conclude by arguing that the expressivist account can explain, as its rivals cannot, what makes vague language useful.

I can say that a building is tall and you can understand me, even if neither of us has any clear idea exactly how tall a building must be in order to count as tall. This mundane fact poses a problem for the view that successful communication consists in the hearer’s recognition of the proposition a speaker intends to assert. The problem cannot be solved by the epistemicist’s usual appeal to anti-individualism, because the extensions of vague words like ‘tall’ are contextually fluid and can be constrained significantly by speakers’ intentions. The problem can be seen as a special case of a more general problem concerning what King has called “felicitous underspecification.” Traditional theories of vagueness offer nothing that can help with this problem. Appeals to diagonalization do not help either. A more radical solution is needed.

One approach to the problem is to keep the orthodox notion of a proposition but innovate in the theory of speech acts. A number of philosophers and linguists have suggested that, in cases of felicitous underspecification, a speaker asserts a “cloud” of propositions rather than just one. This picture raises a number of questions: what norms constrain a “cloudy assertion,” what counts as uptake, and how is the conversational common ground revised if it is accepted? I explore three different ways of answering these questions, due to Braun and Sider, Buchanan, and von Fintel and Gillies. I argue that none of them provide a good general response to the problem posed by felicitous underspecification. However, the problems they face point the way to a more satisfactory account, which innovates in the theory of content rather than the theory of speech acts.

Let me start with a well-known story. Kant held that logic and conceptual analysis alone cannot account for our knowledge of arithmetic: “however we might turn and twist our concepts, we could never, by the mere analysis of them, and without the aid of intuition, discover what is the sum [7+5]” (KrV, B16). Frege took himself to have shown that Kant was wrong about this. According to Frege’s logicist thesis, every arithmetical concept can be defined in purely logical terms, and every theorem of arithmetic can be proved using only the basic laws of logic. Hence, Kant was wrong to think that our grasp of arithmetical concepts and our knowledge of arithmetical truth depend on an extralogical source—the pure intuition of time (Frege 1884, §89, §109). Arithmetic, properly understood, is just a part of logic.

This paper motivates and explores an expressivist theory of vagueness, modelled on Allan Gibbard’s normative expressivism. It shows how Chris Kennedy’s semantics for gradable adjectives can be adjusted to fit into a theory on Gibbardian lines, where assertions constrain not just possible worlds but plans for action. Vagueness, on this account, is literally indecision about where to draw lines. It is argued that the distinctive phenomena of vagueness, such as the intuition of tolerance, can be explained in terms of practical constraints on plans, and that the expressivist view captures what is right about several contending theories of vagueness.

This is a lightly edited version of my comments on Brandom’s Lecture 2, as delivered in Prague at the “Prague Locke Lectures” in April, 2007. I try to say why Brandom’s proposed demarcation is significant, by placing it in a broader context of demarcation proposals from Kant to the twentieth century. I then raise some questions about the basic ingredients of Brandom’s demarcation—the notions of PP-sufficiency and VP-sufficiency—and question whether the vocabulary of conditionals, Brandom’s paradigm for logical vocabulary, can be universal-LX.

In Confusion: A Study in the Theory of Knowledge, Joseph Camp argues that the reasoning of a person who has confused two objects in her thought and talk ought to be appraised using a four-valued relevance logic. I discuss two key moves in Camp’s argument: the assumption that charity to the reasoner requires recognition of her arguments as valid, and the argument that validity for a truth-valueless discourse should not be defined in terms of truth preservation. I then question whether Camp’s four-valued semantics satisfies his own desiderata for a logic of confusion.

Philosophers on all sides of the contextualism debates have had an overly narrow conception of what semantic context sensitivity could be. They have conflated context sensitivity (dependence of truth or extension on features of context) with indexicality (dependence of content on features of context). As a result of this conflation, proponents of contextualism have taken arguments that establish only context sensitivity to establish indexicality, while opponents of contextualism have taken arguments against indexicality to be arguments against context sensitivity. Once these concepts are carefully pulled apart, it becomes clear that there is conceptual space in semantic theory for nonindexical forms of contextualism that have many advantages over the usual indexical forms.

If it is not now determined whether there will be a sea battle tomorrow, can an assertion that there will be one be true? The problem has persisted because there are compelling arguments on both sides. If there are objectively possible futures which would make the prediction true and others which would make it false, symmetry considerations seem to forbid counting it either true or false. Yet if we think about how we would assess the prediction tomorrow, when a sea battle is raging (or not), it seems we must assign the utterance a definite truth-value. I argue that both arguments must be given their due, and that this requires relativizing utterance-truth to a context of assessment. I show how this relativization can be handled in a rigorous formal semantics, and I argue that we can make coherent sense of assertion without assuming that utterances have their truth-values absolutely.

I argue for a new construal of Aristotle’s definition of anagnorisis (recognition) in Poetics 11. Virtually all translators and interpreters of the definition have understood the phrase ton pros eutuchian e dustuchian horismenon as a subjective genitive characterizing the persons involved in the recognition. I argue that it should instead be taken as a partitive genitive characterizing the genus of changes (metabolon) of which recognitions are a species. In addition to being preferable on philogical grounds, the construal I recommend helps illuminate the relation between recognition and reversal (peripeteia) and makes sense of Aristotle’s views about the relative values of various kinds of recognition.

The relativist's central objection to contextualism is that it fails to account for the disagreement we perceive in discourse about "subjective" matters, such as whether stewed prunes are delicious. If we are to adjudicate between contextualism and relativism, then, we must first get clear about what it is for two people to disagree. This question turns out to be surprisingly difficult to answer. A partial answer is given here; although it is incomplete, it does help shape what the relativist must say if she is to do better than the contextualist in securing genuine disagreement

Logic is usually thought to concern itself only with features that sentences and arguments possess in virtue of their logical structures or forms. The logical form of a sentence or argument is determined by its syntactic or semantic structure and by the placement of certain expressions called “logical constants.”[1] Thus, for example, the sentences Every boy loves some girl. and Some boy loves every girl. are thought to differ in logical form, even though they share a common syntactic and semantic structure, because they differ in the placement of the logical constants “every” and “some”. By contrast, the sentences Every girl loves some boy. and Every boy loves some girl. are thought to have the same logical form, because “girl” and “boy” are not logical constants. Thus, in order to settle questions about logical form, and ultimately about which arguments are logically valid and which sentences logically true, we must distinguish the “logical constants” of a language from its nonlogical expressions

Much of The Reason’s Proper Study is devoted to defending the claim that simply by stipulating an abstraction principle for the “number-of” functor, we can simultaneously fix a meaning for this functor and acquire epistemic entitlement to the stipulated principle. In this paper, I argue that the semantic and epistemological principles Hale and Wright offer in defense of this claim may be too strong for their purposes. For if these principles are correct, it is hard to see why they do not justify platonist strategies that are not in any way “neo-Fregean,” e.g. strategies that treat “the number of Fs” as a Russellian definite description rather than a singular term, or employ axioms that do not have the form of abstraction principles.

Much philosophy of logic is shaped, explicitly or implicitly, by the thought that logic is distinctively formal and abstracts from material content. The distinction between formal and material does not appear to coincide with the more familiar contrasts between a priori and empirical, necessary and contingent, analytic and synthetic—indeed, it is often invoked to explain these. Nor, it turns out, can it be explained by appeal to schematic inference patterns, syntactic rules, or grammar. What does it mean, then, to say that logic is distinctively formal?

One of the central themes of Brandom’s work is that we should construct our sematic theories around material validity and incompatibility, rather than reference, truth, and satisfaction. This approach to semantics is motivated in part by Brandom’s pragmatism about the relation between semantics and the more general study of language use—what he calls “pragmatics”: Inferring is a kind of doing. . . . The status of inference as something that can be done accordingly holds out the promise of securing an appropriate relation between pragmatics, the study of the practices, and semantics, the study of the corresponding contents. (MIE, 91)1 Although Brandom does not go so far as to say that a pragmatist attitude to the relation between semantics and pragmatics requires an inferentialist semantics, his motivating arguments strongly suggest that a pragmatist ought to be an inferentialist. In what follows, I discuss the connections between Brandom’s pragmatism and his inferentialism. I’ll argue that pragmatism, as Brandom initially describes it—the view that “semantics must answer to pragmatics”—does not favor an inferentialist approach to semantics over a truth-conditional one. I’ll then consider whether inferentialism might be..