 Given the different roles for “if” just identified, it is hardly surprising that generalisations about necessary and/or sufficient conditions are hard to formulate. Suppose, for example, someone tries to state a sufficient condition for a seminar being good in a context where the speaker and all the listeners share the view that Solange’s presence is a reason why seminars would be good. In this case, Solange’s presence might be said to be a sufficient condition of the seminar being good in the sense that her presence is a reason why it is good. Now, is there a similar sense in which the goodness of the seminar is a necessary condition of Solange’s presence? The negative answer to this question is already evident from the earlier discussion. If we follow von Wright’s proposal, mentioned above, we get the following result: that the seminar is not good is a sufficient condition of Solange not being present. But this cannot plausibly be read as a sufficient condition in anything like the sense of a reason why. At most, the fact of the seminar not being a good one may be a reason for thinking that Solange was not at it. So how can we tell, in general, what kind of condition is being expressed in an “if” sentence? As noted in the case of the sea battle, when rewriting in the formal mode captures the sense of what is being said, and when the formulations “if p, q” and “p only if q” seem idiomatically equivalent, then an inferential interpretation will be in order, von Wright’s equivalences will hold, and the material conditional gives a reasonable account of such cases. As indicated above, there are limitations to such an approach and it provides at best a partial account of the circumstances under which conditional sentences express necessary or sufficient conditions.