On Explaining Linguistic Competence

Abstract

In a number of papers, and most recently in his book Subject and Predicate in Logic and Grammar, P. F. Strawson has enquired how our understanding of sentences and of the relations between sentences is connected to our grasp of the logical structure of those sentences. For example, any action-ascribing sentence with adverbial modifiers entails any sentence obtained by deleting some or all of the modifiers. Strawson asks how we are to explain our grasp of the structure of these entailments.' The structure in question is logical structure, but what is logical structure or the logical structure of language, how does it differ from grammatical structure? What does the 'grasp' of the logical structure of a sentence give us that the 'grasp' of its grammatical form does not? These questions might be easy to answer if it were the case that the grammatical rules of language were simply to be identified with instructions (or, better, prohibitions) concerning the construction of wellformed sentences. We could then say that the rules of grammar determine meaningfulness, but that the logical structure of a sentence indicates the contribution of each part of the sentence to the meaning of the whole, and indicates the logical relations in which that sentence can stand to other sentences. The trouble is that the statement of grammatical rules requires a recognition in the grammar of different categories of expression. Yet it is precisely by the identification of different sorts of expression that the logical form of sentences is ascertained. And the grammarian is not restricted to assigning a category to each word appearing in any sentence. He can, for example, recognize which part of 'ambulo' has to do with walking and which part has to do with me. Russell's Theory of Definite Descriptions has often been regarded as a paradigm of the means of distinguishing logical from grammatical form. But why should not the grammarian distinguish, among subject-terms, proper names from descriptions and perhaps other kinds of subject-term? Why in fact, should we not just identify grammatical form and logical form? Someone who wanted to oppose such an identification might argue that there is no justification for anyone thus postulating a greater complexity of syntax than has heretofore been recognized to account for entailments with which his previous account had not been able to deal. After all, if it were intuitively recognized that SI entails S2, but that our account of the grammatical form of SI and S2 did not make this evident, then why not simply say that SI, S2 had grammatical features F1, F2 respectively and that for any pair of sentences, if the first has F1 and the second F2, then the first entails the second? Obviously because this would be a useless ad hoc manoeuvre.