Externalization Of Language

The fact that the language faculty provides the means to generate infinitely many expressions is virtual truism, but one finds scant attention to it until about 50 years ago. One reason is that it was only by mid-twentieth century that the concept of recursive generation was clearly enough understood within logic and mathematics so that it became possible to pose seriously the question of how language makes use of some such procedure. However, the basic observation can be traced back to the early scientific revolution: to Galileo, in side remarks, and particularly to Descartes, for whom it was at the core of his theory of mind and body. The most striking difference between humans and animals or machines, Descartes argued, was that all humans,

The simplest assumption, hence the one we adopt unless counterevidence appears, is that the generative procedure emerged suddenly as the result of a minor mutation. In that case we would expect the generative procedure to be very simple. Various kinds of generative procedures have been explored in the past 50 years. One approach familiar to linguists and computer scientists is phrase structure grammar, developed in the 1950s and since extensively employed. The approach made sense at the time.

It captured at least some basic properties of language, such as hierarchic structure and embedding. Nevertheless, it was quickly recognized that phrase structure grammar is not only inadequate for language but is also quite a complex procedure with many arbitrary stipulations, not the kind of system we would hope to find, and unlikely to have emerged suddenly. Over the years, research has found ways to reduce the complexities of these systems, and finally to eliminate them entirely in favor of the simplest possible mode of recursive generation: an operation that takes two objects already constructed, call them X and Y, and forms from them a new object that consists of the two unchanged, hence simply the set with X and Y as members. Call this operation Merge. Provided with conceptual atoms

External merge can add something new, yielding “Eagle can swim.” That carries us part of the way towards displacement. In “can eagle can swim,” the phrase “can” appears in two positions, and in fact those two positions are required for semantic interpretation: the original position provides the information that “can” is understood to be the direct object of