There are two ways of thinking about the syntax-semantics interface. One involves grounding meaning of sentences in descriptions of the world that make them true and investigating the feeding relationship between syntactic representations and truthmakers in this sense. This is a descriptive enterprise, and gives rise to computational proposals involving language specific abstract semantic representations mediating between the syntactic representation and truth conditions. We could call this Syn-Sem^E. This is not inconsistent with the strong minimalist thesis construed in the way I have argued it can be in Part II, but it is not directly pursuing it.

It is important to reiterate that the formal semanticists use of an intermediate logical language (the semantic representation) is widely considered by the field to be at the level of a computational theory in the sense of Marr (1982), and is not intended to encode internal mental representations of meaning in any psychologically real fashion.

I suspect however, that many people working at what they think of as the syntax-semantics interface think they are doing something different from straight up formal semantics. Unlike the classical formal semanticist, some of these do not use the semantic representational node as merely an instrumental device to mediate between the syntax and truth conditions (seeking accuracy, efficiency and elegance in doing so but no more). They are often also interested in exploring the relation between two systems of representation both of which are internal, and in understanding how the syntactic system of language discretizes and categorizes in order to create a workable symbolic tool for the mind, while still liaising with the brain’s general, language independent cognitive machinery. (I think, for example, that this is what Jackendoff in his work means by Semantics.)

An internalized semantic representation system that is tightly coupled to linguistic representations could be called I-semantics, since it does not represent facts about the world, but is an aspect of the mature I-language system of an individual speaker/hearer (in Chomsky’s 1986 sense in Knowledge of Language).

Thus, the other way of looking at the syntax-semantics interface is in terms of. seeking explanations for the way syntax turns out to be. For this particular set of research questions we are interested in humans’ mental representations of meaning as the mutually determining factor interfacing with syntax. We could call this Syn-Sem^I . The pursuit of the questions concerning this latter interface could be considered a direct pursuit of a strong minimalist agenda. It will inevitably feed off the results of Syn-Sem^E, as described above, but also of the results of cognitive science, psycho and neuro-linguistics.

When it comes to explanatory influence, there is I contend, a clear asymmetry between the two interfaces classically referred to in minimalist theorizing. The externalization of the system is a highly variable and contingent, and known to preserve functionality across the modality of auditory vs. gestural sign. Externalization per se is arguably one of the design factors of language, but the exact mode of externalization demonstrably not. On the other hand, the domain of generalized cognition that syntax is embedded within presumably does not and cannot vary from language to language. Our highly complex human systems of thought and categorization are the source domain for language, and language is an extension of our superior cognitive abilities in apprising, categorizing the world. The human mind is the crucible within which language evolved in the first place, and while one does not need to accept the idea that language `evolved for communication’ of our thoughts about the world, it certainly plays a symbiotic role in our ability to both cognize and represent our own thoughts to ourselves.

Importantly, human language is not just a big bag of conventionalized symbols triggered by episodic stimulus in the world, it differs from other living creatures’ signalling systems in a number of striking ways, and share properties with those systems in others. Arbitrariness of the sign, and externalization of signal can be found in systems throughout the natural world, from monkey calls to mating dances, from songbird tunes to pheromones. But these collections of arbitrary signs do not have a syntax, and they do not systematically require the detailed tracking of the perspective of other minds; the property of creative open ended composition of meaning is unique to humans (apparently).

It is important therefore to emphasize that mere sign-sign relationships (systematic combinatorics) is not sufficient to create the natural language `magic’. Birdsong has been shown to have some form of syntax, in the sense of brute combinatorics, but does not have semanticity. By this I mean that the units that combine and relate to each other in systematic ways do not correspond to meaning units that also undergo composition in parallel. It is the combination of syntax and semanticity that creates open ended meaning composition which is the core innovation of the human species (cf. also Miyagawa et al. 2014 ). The recursive composition process that syntax affords is the feature that delivers creative meaning composition that can be coded and decoded reliably by human minds.

So in terms of deep properties of natural languages (NLs), I would argue that the interface with the internal systems of cognition is not an interface that is completely parallel to the interface with sound perception and production. The former is the interface with the source domain for the content being represented, while the latter is the contingent mode of externalization. Intuitively, the point of language is not to produce sound (this, for example, might be point of music), the point of language is the expression of internal patterns of thought (whether for oneself or others).

If we are to probe the question of what particular aspects of the mature working grammar emerge based on independent features of human thought, then we need to ask a different kind of question about the nature of the representations that the mature syntactic competence traffics in. Broadly speaking, we could characterize these questions as follows:

A. Are there mutually determining relations in the way syntax maps to thought, either with respect to primitive categories or the relations between them?

B. Are these hardwired or developmentally guided? What is the scope of variation in what is learnable in this domain?

C. To what extent do the features and categories reified in the syntax feed back into general cognition and start having an effect on our abilities to think abstractly and creatively?

These questions are at the heart of what I take to be the field of syntax-semantics within a specifically minimalist agenda, and of morphosemantics too, if morphology is a kind of syntax. Crucially, since the minimalist programme is stated in terms of the mind/brain of the individual, the core questions here refer to internal representations of meaning. So the Syn-Sem interface here is actually a somewhat different research programme from the one formal semantics is classically engaged, and is based on an understanding of what I-Semantics looks like. Unlike the intermediate representations of E-semantics, there is a right or wrong of the matter when it comes to postulating I-semantic representations. This already brings its own methodological differences and challenges. More of which in my next post.