 An alternative view is that different kinds of dependency are expressed by use of the conditional construction: (iv) is not equivalent to (iii) because the consequent of (iii) provides what might be called a reason for thinking that Lambert has learned to play the cello. By contrast, the very same condition—that I buy Lambert a cello—appears to fulfil a different function in (iv) (namely that I first have to buy him a cello before he learns to play). In the following section, the possibility of distinguishing between different kinds of conditions is discussed. The existence of such distinctions would seem to provide some evidence for a systematic ambiguity about the meaning of “if” and in the concepts of necessary (and sufficient) condition.