 On the other hand, assume that \(q\) is a contingently necessary proposition, that is, that it is possible that \(q\) is necessary and possible that \(q\) is not necessary. By S5, we get that it is necessary that \(q\) is necessary, making it impossible that \(q\) is not necessary. As a result, it is both possible and not-possible that \(q\) is not necessary, which likewise shows that \(q\) cannot be a contingently necessary proposition. The only other option is that \(q\) is a necessary truth, which would beg the question. Thus, the argument fails by being unable to characterize \(q\). For rebuttals, see Gale and Pruss (2002) and Rutten (2012: 84–87, see Other Internet Resources).