THE PRESENT PERFECT PUZZLE

In Chris has left York, it is clear that the event in question, Chris's leaving York, has occurred in the past, for example yesterday at ten. Why is it impossible, then, to make this event time more explicit by such an adverbial, as in *Yesterday at ten, Chris has left York? Any solution to this puzzle crucially hinges on the meaning assigned to the perfect, and the present perfect in particular. Two such solutions, a scope solution and the 'current relevance' solution, are discussed and shown to be inadequate. A new, strictly compositional analysis of the English perfect is suggested, and it is argued that the incompatibility of the present perfect and most past tense adverbials has neither syntactic nor semantic causes but follows from a simple pragmatic constraint, called here the POSITION-DEFINITENESS CONSTRAINT. The same constraint also makes an utterance such as At ten, Chris had left at nine pragmatically odd, even if Chris indeed had left at nine, so that the utterance is true.