C. contends that a verb, instead of having one constant presupposition, has a chain of hierarchically ordered presuppositions (e.g. for 'manage': try - difficulty - unlikelihood). These presuppositions are called 'vanishing' because the hearer, in trying to understand an utterance, moves down the hierarchy and eliminates possibilities until he arrives at the appropriate one. Vanishing presuppositions are presented as a special case of progressively extended frames.