 If two people are arguing “If \(p\), then \(q\)?” and are both in doubt as to \(p\), they are adding \(p\) hypothetically to their stock of knowledge and arguing on that basis about \(q\); so that in a sense “If \(p\), \(q\)” and “If \(p\), \(\neg q\)” are contradictories. We can say that they are fixing their degree of belief in \(q\) given \(p\). If \(p\) turns out false, these degrees of belief are rendered void. If either party believes not \(p\) for certain, the question ceases to mean anything to him except as a question about what follows from certain laws or hypothesis. [Notation adapted]