Online research in philosophy

Certain anti-realisms about mathematics are distinguished by their taking proof rather than truth as the central concept in the account of the meaning of mathematical statements. This notion of proof which is meaning determining or canonical must be distinguished from a notion of demonstration as more generally conceived. This paper raises a set of objections to Dummett's characterisation of the notion via the notion of a normalised natural deduction proof. The main complaint is that Dummett's use of normalised natural deduction proofs relies on formalisation playing a role for which it is unfit. Instead I offer an alternative account which does not rely on formalisation and go on to examine the relation of proof to canonical proof, arguing that rather than requiring an explicit characterisation of canonical proofs we need to be more aware of the complexities of that relation.

Primarily a response to Paul Horwich's "Composition of Meanings", the paper attempts to refute his claim that compositionality—roughly, the idea that the meaning of a sentence is determined by the meanings of its parts and how they are there combined—imposes no substantial constraints on semantic theory or on our conception of the meanings of words or sentences. Show Abstract.

In the context of debates about what form a theory of meaning should take, it is sometimes claimed that one cannot understand an intersective modifier-head construction (e.g., ‘pet fish’) without understanding its lexical parts. Neo-Russellians like Fodor and Lepore contend that non-denotationalist theories of meaning, such as prototype theory and theory theory, cannot explain why this is so, because they cannot provide for the ‘reverse compositional’ character of meaning. I argue that reverse compositionality is a red herring in these debates. I begin by setting out some positive arguments for reverse compositionality and showing that they fail. Then I show that the principle of reverse compositionality has two big strikes against it. First, it is incompatible with all theories of meaning on the market, including the denotationalism favored by neo-Russellians. Second, it explains nothing that is not already explained by its venerable predecessor, the principle of (forward) compositionality.

Reverse Compositionality (RC) is the thesis that one understands a complex expression only if one understands its parts. I argue that this thesis is false for natural languages. I then argue that the phenomenon that motivates the thesis is more likely to be a fact about human sentence-processing than linguistic understanding per se. Finally, I argue that RC is not useful in the debates about prototype-style theories of concepts in which it figures heavily.

Jerry Fodor and Ernie Lepore have argued that inferential roles are not compositional. It is unclear, however, whether the theories at which they aim their objection are obliged to meet the strong compositionality requirement they have in mind. But even if that requirement is accepted, the data they adduce can in fact be derived from an inferential-role theory that meets it. Technically this is trivial, but it raises some interesting objections turning on the issue of the generality of inferential roles. I explain how those objections can be met. Whether Fodor’s and Lepore’s strong compositionality requirement is justified or not, then, inferential-role theories do not have the problem that they claim to have identified.

The central premise of Michael Dummett's global argument for anti-realism is the thesis that a speaker's grasp of the meaning of a declarative, indexical-free sentence must be manifested in her uses of that sentence. This enigmatic thesis has been the subject of a great deal of discussion, and something of a consensus has emerged about its content and justification. The received view is that the manifestation thesis expresses a behaviorist and reductive theory of meaning, essentially in agreement with Quine's view of language, and motivated by worries about the epistemology of communication. In the present paper I begin by arguing that this standard interpretation of the manifestation thesis is neither particularly faithful to Dummett's writings nor philosophically compelling. I then continue by reconstructing, from Dummett's texts, an account of the manifestation thesis, and of its justification, that differ sharply from the received view. On my reading, the thesis is motivated not epistemologically, but conceptually. I argue that connections among our conceptions of meaning, assertion, and justification lead to a conclusion about the metaphysics of meaning: we cannot form a clearly coherent conception of how two speakers can attach different meanings to a sentence without at the same time differing in what they count as justifying assertions made with that sentence. I conclude with some suggestions about how Dummett's argument for global anti-realism should be understood, given my account of the manifestation thesis.

This paper contains a discussion of how the concept of compositionality is to be extended from context invariant to context dependent meaning, and of how the compositionality of natural language might conflict with context dependence. Several new distinctions are needed, including a distinction between a weaker (e-) and a stronger (ec-) concept of compositionality for context dependent meaning. The relations between the various notions are investigated. A claim by Jerry Fodor that there is a general conflict between context dependence and compositionality is considered. There is in fact a possible conflict betwee ec-compositionality and context dependence, but not of the kind Fodor suggests. It turns on the presence of so-called unarticulated constituents, in John Perry’s sense. Because of this phenomenon, on some semantic accounts there might be a variation in the meaning of a complex expression between contexts without any corresponding variation in any of the syntactic parts of that complex. The conflict can be resolved in several ways. One way is to make the unarticulated context dependence explicit only in the meta-language, which makes it into an unarticulated constituent account. A recent argument by Jason Stanley against such accounts is discussed. According to Stanley, certain readings of English sentences involving binding of contextual variables, are unavailable in these theories. After considering a reply to Stanley by François Recanati, I present an outline of a fully compositional theory, of the unarticulated constituent variety, which does deliver these readings. Concluding remarks on, inter alia, the semantics/pragmatics distinction.

I address the question whether Dummetts manifestation challenge to semantic realism can be disarmed by reflection on the compositionality of meaning. Building on work of Dummett and Wright, I develop in §§12 what I argue to be the most formidable version of the manifestation challenge. Along the way I review attempts by previous authors to deploy considerations about compositionality in realisms favour, and argue that they are unsuccessful. The formulation of the challenge I develop renders explicit something which I argue to be implicit in Dummetts and Wrights presentations: that the challenge depends on a contention about the constitution of speakers states of declarative sentence understanding: i.e., that many such states incorporate abilities to recognize whether the associated sentences truth conditions are satisfied. In §3 I argue that reflection on the compositionality of meaning reveals, first, that this contention must be rejected by the realist, and second, that it is unmotivated. This result does not settle the debate over the manifestation challenge, but it implies that the onus of argument does not currently rest with the realist.

Ordinary semantic compositionality (meaning of whole determined from meanings of parts plus composition) can serve to explain how a hearer manages to assign an appropriate meaning to a new sentence. But it does not serve to explain how the speaker manages to find an appropriate sentence for expressing a new thought. For this we would need a principle of inverse compositionality, by which the expression of a complex content is determined by the expressions of it parts and the mode of composition. But this presupposes that contents have constituent structure, and this cannot be taken for granted. However, it can be proved that if a certain principle of substitutivity is valid for a particular language, then the meanings expressed by its sentences can justifiably be treated as structured. In its simplest form, this principle says that if in a complex expression a constituent is replaced by another constituent with a different meaning, the new complexhas a meaning different from the original. This principle is again inversely related to the normal compositional principle of substitutivity. The combination of ordinary and inverse compositionality is here called strong compositionality. The proof is carried out in the algebraic framework developed by Wilfrid Hodges and Dag Westerståhl.

In Michael Dummett’s manifestability challenge to truth conditional semantics, it is argued that the meaning of sentence cannot be its truth conditions, for then a speaker’s knowledge of the meaning would not in all cases be manifestable. In those cases, the speaker would not know how to find out whether the truth conditions are satisfied or not. By contrast, knowledge of what counts as a proof of a sentence would pass the manifestability test, since a speaker is supposed always to be capable of deciding whether or not a given object is a proof of a given sentence. There is a problem for the positive part, however, for there is no guarantee that a compositional proof-theoretic semantics in all cases provides knowledge sufficient for recognizing any proof of a provable sentence for which the meaning is given. In those cases, the speaker need not know how to find out whether a given object is a proof of the sentence. Hence, if knowledge of meaning is required to be manifestable, there is no guarantee in general is compositionally specifiable.