Given the present state of transformational grammar theory, it is virtually impossible to provide convincing support for, or (and this, of course, is more serious) evidence against, any single hypothesis. Between 1957 and 1965, revisions of the theory and new hypotheses were generally proposed one or two at a time and tested within the otherwise widely accepted theoretical framework (the ‘paradigm’: Kuhn 1962). However, in recent years just about everything but the need for transformations to pair more abstract objects with actual and/or potential linguistic objects has been called into question or affected somehow by new hypotheses. Consequently, linguists must realize that any evidence they attempt to marshal for or against a particular hypothesis can be refuted or circumvented by at least one combination of other apparently unrelated popular hypotheses (abetted by the excessive power of transformational rules: Peters 1970).

All treatments of so-called to-contraction in English (Lakoff (1970), Bresnan (1971), Lightfoot (1976)) attempt to deal with this phenomenon entirely in terms of contiguity. The purpose of this squib is to point out that the major constraint on this phenomenon is rather one of subject coreference, and furthermore that this coreference condition is identical to that for a universal rule which I have called ‘equi-subject clause union’ (Frantz 1976).

To illustrate, I will reconsider typical examples cited in discussions of this phenomenon, pointing out the relevance of coreference.