Many studies of language, whether in philosophy, linguistics, or psychology, have focused on highly developed human languages. In their highly developed forms, such as those employed in scientific discourse, languages have a unique set of properties that have been the focus of much attention. For example, descriptive sentences in a language have the property of being "true" or "false," and words of a language have senses and referents. Sentences in a language are structured according to complex syntactic rules. Theorists focusing on language are naturally led to ask questions such as what constitutes the meanings of words and sentences and how the principles of syntax are encoded in the heads of language users. Although there is an important function for inquiries into the highly developed forms of these cultural products

46 BECHTEL (Abrahamsen, 1987), such a focus can be quite misleading when we want to explain how these products have arisen or account for the human capacity to use language. The problem is that focusing on the most developed forms makes linguistic ability seem to be a sui generis phenomenon not related to, and hence not explicable in terms of, other cognitive capacities. Chomsky's (1980) postulation of a specific language module equipped with specialized resources needed to process language and possessed only by humans is not a surprising result.