ABSTRACT
This chapter investigates the causes of rule incompatibility by considering numerous examples of incompatible rules and shows that their mutual incompatibility reduces on each occasion to at least one of a small number of syntactic oppositions between their respective conditions of application. There is direct evidence, first, about the output structures of the grammaticality-predicting syntactic rules whose outputs actually show up in surface structures. Second, the incompatibility of many of the rules by simply comparing sets of surface sentences. Thirdly, the native speaker supplies with information on the meaning of the grammatical surface sentences. Returning to the rule incompatibilities should be able to decide, by matching these three sets of facts, whether the cause of some incompatibility either is or is not semantic. In the sample of rule pairs discussed the total incompatibilities includes: Relative Clause Reduction and Extraposition from NP, Be-contraction and Predicate Adjective Fronting, all fronting root transformations, Affix-hopping and Do-support, and the Phrase-structure rule incompatibilities.
