 Consider the formula or the law: \(F\) entails \(G\). How can a particular proposition, or more briefly, a fact affect its probability? If this fact consists of the presence of \(G\) in a case of \(F\), it is favourable to the law […]; on the contrary, if it consists of the absence of \(G\) in a case of \(F\), it is unfavourable to this law. (219, notation slightly adapted)