Paul Pietroski

This chapter argues that liar sentences reveal a fundamental problem for the project of characterizing linguistic meaning in terms of truth. It further argues that weak-logic solutions to the Foster problem for Davidsonian theories are exacerbated by the Liar. According to the chapter, liar sentences have no truth conditions, and any theory that has its instances of the T-schema as a theorem is just false. The author urges that liar sentences illustrate a deep difficulty for truth-theoretic conceptions of meaning for Human Languages and that we should find a different conception of meaning according to which expressions of Human Languages—I-Languages—are not among the truth-evaluable things.

This chapter presents detailed empirical work on several aspects of children's linguistic performance, focusing in particular on evidence that even two-year-old children understand that the meanings of determiners are ‘conservative’, that the meaning of natural language disjunction is ‘inclusive–or’, and that the structural notion of ‘c-command’ governs a range of linguistic phenomena. This and other works are used to defend three related versions of the argument from the poverty of the stimulus, each of which strongly supports the existence of an innate language faculty.

Frege's account of opacity is based on two attractive ideas: every meaningful expression has a sense (Sinn) that determines the expression's semantic value (Bedeutung); and the semantic value of a‘that’‐clause is the thought expressed by its embedded sentence. Considerations of compositionality led Frege to a more problematic view: inside ‘that’‐clauses, an expression does not have its customary Bedeutung. But contrary to initial appearances, compositionality does not entail a familiar substitutivity principle. And Fregeans can exploit this point in a way that lets them reject Bedeutung‐shifting.

The philosophical problem of mental causation concerns a clash between commonsense and scientific views about the causation of human behaviour. On the one hand, commonsense suggests that our actions are caused by our mental states—our thoughts, intentions, beliefs and so on. On the other hand, neuroscience assumes that all bodily movements are caused by neurochemical events. It is implausible to suppose that our actions are causally overdetermined in the same way that the ringing of a bell may be overdetermined by two hammers striking it at the same time. So how are we to reconcile these two views about the causal origins of human behaviour? One philosophical doctrine effects a nice reconciliation. Neuralism, or the token-identity theory, states that every particular mental event is a neurophysiological event and that every action is a physically specifiable bodily movement. If these identities hold, there is no problem of causal overdetermination: the apparently different causal pathways to the behaviour are actually one and the same pathway viewed from different perspectives. This attractively simple view is enjoying a recent revival in fortunes

Quantificational determiners are often said to be devices for expressing relations. For example, the meaning of _every_ is standardly described as the inclusion relation, with a sentence like _every frog is green_ meaning roughly that the green things include the frogs. Here, we consider an older, non-relational alternative: determiners are tools for creating restricted quantifiers. On this view, determiners specify how many elements of a restricted domain (e.g., the frogs) satisfy a given condition (e.g., being green). One important difference concerns how the determiner treats its two grammatical arguments. On the relational view, the arguments are on a logical par as independent terms that specify the two relata. But on the restricted view, the arguments play distinct logical roles: specifying the limited domain versus supplying an additional condition on domain entities. We present psycholinguistic evidence suggesting that the restricted view better describes what speakers know when they know the meaning of a determiner. In particular, we find that when asked to evaluate sentences of the form _every F is G_, participants mentally group the Fs but not the Gs. Moreover, participants forego representing the group defined by the intersection of F and G. This tells against the idea that speakers understand _every F is G_ as implying that the Fs bear relation (e.g., inclusion) to a second group.

Noam Chomsky offered a fruitful conception of the languages that children regularly acquire and use in human speech. In discussions of meaning, Chomsky often emphasizes complexities of usage and warns against theories that identify word meanings with sets of things that the words are allegedly “true of.” While syntactic structure plays an important role in determining the conditions on reference that complex expressions impose, Chomsky denied that the semantic role of syntax is adequately characterized as a mapping from syntactic structures and extensions of lexical items to extensions of complex expressions. Chomsky began by describing languages as sets of sentences, with sentences described as strings of “formatives.” This familiar simplification was pedagogically useful. It let Chomsky distinguish importantly different kinds of recursive procedures, without yet discussing homophony.

We can use language to say what people did, often describing the same action in different complex ways. Davidson offered an illuminating analysis of action reports like “Miss Scarlet stabbed Colonel Mustard with a dagger in the library,” which involve adverbial modifiers. Part of the challenge here is to say how such modifiers are semantically related to the rest of the sentence. Building on the ancient observation that verbs are often used to describe what happened, Davidson argued that an action report implies the occurrence of an eventthat meets the conditions specified by the report; where an event can be described in endlessly many ways. In this chapter, I review Davidson's account, his arguments in favor of it, and his responses to some initial objections. I also discuss some subsequent work that supports central aspects of Davidson's proposal while also presenting challenges for combining his analysis of action reports with his broader conception of linguistic meaning.

A sentence like every circle is blue might be understood in terms of individuals and their properties or in terms of a relation between groups. Relatedly, theorists can specify the contents of universally quantified sentences in first-order or second-order terms. We offer new evidence that this logical first-order vs. second-order distinction corresponds to a psychologically robust individual vs. group distinction that has behavioral repercussions. Participants were shown displays of dots and asked to evaluate sentences with each, every, or all combined with a predicate. We find that participants are better at estimating how many things the predicate applied to after evaluating sentences in which universal quantification is indicated with every or all, as opposed to each. We argue that every and all are understood in second-order terms that encourage group representation, while each is understood in first-order terms that encourage individual representation. Since the sentences that participants evaluate are truth-conditionally equivalent, our results also bear on questions concerning how meanings are related to truth-conditions.

In Conjoining Meanings, I argue that meanings are composable instructions for how to build concepts of a special kind. In this summary of the main line of argument, I stress that proposals about what linguistic meanings are should make room for the phenomenon of lexical polysemy. On my internalist proposal, a single lexical item can be used to access various concepts on different occasions of use. And if lexical items are often “conceptually equivocal” in this way, then some familiar arguments for externalist conceptions of linguistic meaning need to be reevaluated.

Davidson conjectured that suitably formulated Tarski-style theories of truth can “do duty” as theories of meaning for the spoken languages that humans naturally acquire. But this conjecture faces a pair of old objections that are, in my view, fatal when combined. Foster noted that given any theory of the sort Davidson envisioned, for a language L, there will be many equally true theories whose theorems pair endlessly many sentences of L with very different specifications of whether or not those sentences are true. And if L includes words ‘true’, then for reasons stressed by Tarski, it’s hard to see how any truth theory for L could be correct. Moreover, each of these concerns amplifies the other. Appealing to possible worlds will not help with Foster’s Problem, for reasons that Chomsky discussed in the 1950s, and appealing to trivalent models of truth will not avoid concerns illustrated with Liar Sentences.