 These oddities might be dismissed as mere anomalies were it not for the fact that writers have identified a number of other problems associated with the ideas of reciprocity and equivalence mentioned at the end of the previous section. According to the standard theory, there is a kind of reciprocity between necessary and sufficient conditions, and “if p, q” sentences can always be paraphrased by “p only if q” ones. However, as writers in linguistics have observed, neither of these claims matches either the most natural understanding of necessary (or sufficient) conditions, or the behaviour of “if” (and “only if”) in English. Consider, for example, the following case (drawn from McCawley 1993, p. 317):