Introduction

In section 3.7 I sketched the outlines of a theory of phonology that was distilled from the leading ideas discussed in chapter 3. This theory adopts the Contrastivist Hypothesis, which holds that phonology computes only contrastive features. It determines what the contrastive features in a language are by applying the SDA to a contrastive feature hierarchy for that language. In keeping with the Contrastivist Hypothesis, phonological activity serves as the chief heuristic for determining what the feature hierarchy is for a given language.

Though the ingredients for such a theory were in place by the 1930s, phonological theory did not develop in this direction; why it did not was the subject of chapters 4–6. These chapters show that the theory of section 3.7 has never properly been put to the test. In this chapter I argue that these ideas remain viable and indispensable to an explanatory theory of phonology.

Of course, any contemporary effort to implement such a theory must take account of advances in phonology since the 1930s. For example, the diagnostic given in (38d) of chapter 3, that a contrastive feature must be present in all the allophones of a phoneme, is not consistent with the generative phonological conception that phonology is relatively abstract with respect to phonetics. In keeping with Chomsky and Halle's arguments against taxonomic phonemics, it is unlikely that we can put limits on the degree to which a segment may be modified in the course of a derivation.