The morpheme structure constraints of classic generative phonology impose language-particular restrictions on underlying representations. It has long been known that MSCís often duplicate the functions of rules or output constraints, and so Stampe, Prince & Smolensky, and others have proposed to eliminate them. In OT, the descriptive effects of MSC’s are obtained from rankings that compel neutralization of potential underlying distinctions. One input is said to occult the other when both map onto a common output.
This paper has focused on MSC’s that prevent alternations within a paradigm. Absence of alternation is an effect of high-ranking output-output faithfulness constraints which enforce intra-paradigmatic invariance. By the proper deployment of OO faithfulness, neutralization of a potential underlying distinction is carried over from a simple form to words derived from it. In this way, occultation is extended from the word to the paradigm.
Two examples were studied in detail, word minimality in Kansai Japanese and the phonology of root-final consonants in Makassarese. By their very nature, these phenomena make sense only in terms of output constraints. Except by stipulation, they cannot be analyzed with classic MSCís, and so they support this overall approach.