IntroductionThe central notion of structural linguistics is that of contrast or opposition: The linguistic value and role of a unit cannot be reduced to its physical substance, but is crucially determined by the network of relations that it enters into with other units of a similar kind: phoneme to phoneme, morpheme to morpheme, etc. A mid front vowel /e/ in a five-vowel system is something quite different from an /e/ in a seven-vowel system, perfect tense in a system without imperfect is something different from perfect tense in a system with imperfect, etc. Structuralist phonemics is the embodiment of a theory built on contrast as a central notion.Generative phonology, on the other hand, was virtually founded on the rejection of a strictly phonemic level of representation where all and only the contrastive units of a sound system are represented (Halle 1962). The focus was instead on the new device of the phonological derivation, with a sequence of phonological rules deriving phonetic output representations from abstract morphophonemic inputs. Neither of these two levels served as a representation of contrastive function in the sense of structuralist phonemics, and there was also no formal separation into rules neutralizing contrasts between phonemes and rules deriving allophones. All in all, classical generative phonology had little use for contrast as an operative element of the theory, and the notion was perceived as functionalist and unfit for the rigors of formal analysis.
1Recent work has seen an impressive re-emergence of contrast as a key element of phonological theory and analysis. Within OT Phonology, the work of Flemming 1995and Padgett 2003 showed that considerations of contrastive function need not remain at the level of vague appeals to trends and tendencies, but can be given a precise formal expression that is fully integrated with the rest of the grammar.The purpose of this note is to take up an example of a contrast-effect in morphology from Japanese, the so-called ra-dropping or ra-nuki (ら抜き, lit. 'ra-pullout') in the potential form of * We are grateful to Haruo Kubozono, Jaye Padgett, John Whitman, and an anonymous reviewer for useful suggestions, as well as to audiences at the 2003 Phonology Forum (Kobe College) and at colloquia at UC Santa Cruz and at Cornell University. 1 Every descriptively adequate theory of phonology needs a way of distinguishing contrasting segments from non-contrasting pairs of segments. In the further development of generative phonology, this task fell to underspecification, with non-contrastive features being left out in underlying representations and filled in by rule in the course of the derivation. Underspecification has been found to have fundamental problems and paradoxes (see McCarthy andTaub 1992 andSteriade 1995) and has been largely abandoned in OT (see Smolensky 1993 and subsequent work for arguments).