John MacFarlane

We consider a paradox involving indicative conditionals (‘ifs’) and deontic modals (‘oughts’). After considering and rejecting several standard options for resolv- ing the paradox—including rejecting various premises, positing an ambiguity or hidden contextual sensitivity, and positing a non-obvious logical form—we offer a semantics for deontic modals and indicative conditionals that resolves the paradox by making modus ponens invalid. We argue that this is a result to be welcomed on independent grounds, and we show that rejecting the general validity of modus ponens is compatible with vindicating most ordinary uses of modus ponens in reasoning.

According to Semantic Minimalism, every use of "Chiara is tall" (fixing the girl and the time) semantically expresses the same proposition, the proposition that Chiara is (just plain) tall. Given standard assumptions, this proposition ought to have an intension (a function from possible worlds to truth values). However, speakers tend to reject questions that presuppose that it does. I suggest that semantic minimalists might address this problem by adopting a form of "nonindexical contextualism," according to which the proposition invariantly expressed by "Chiara is tall" does not have a context-invariant intension. Nonindexical contextualism provides an elegant explanation of what is wrong with "context-shifting arguments" and can be seen as a synthesis of the (partial) insights of semantic minimalists and radical contextualists.

According to “sensitive invariantism,” the word “know” expresses the same relation in every context of use, but what it takes to stand in this relation to a proposition can vary with the subject’s circumstances. Sensitive invariantism looks like an attractive reconciliation of invariantism and contextualism. However, it is incompatible with a widely-held view about the way knowledge is transmitted through testimony. If both views were true, someone whose evidence for p fell short of what was required for knowledge in her circumstances could come to know that p simply by feeding her evidence to someone in less demanding circumstances and then accepting his testimony.

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..

It is taken for granted in much of the literature on vagueness that semantic and epistemic approaches to vagueness are fundamentally at odds. If we can analyze borderline cases and the sorites paradox in terms of degrees of truth, then we don’t need an epistemic explanation. Conversely, if an epistemic explanation suffices, then there is no reason to depart from the familiar simplicity of classical bivalent semantics. I question this assumption, showing that there is an intelligible motivation for adopting a many-valued semantics even if one accepts a form of epistemicism. The resulting hybrid view has advantages over both classical epistemicism and traditional many-valued approaches.