I am going, then, to express the universal proposition, with regard to two particular properties and, which asserts that Whatever has, has or If anything has, it has, without asserting that anything has, by a means of expressing it, which since we have adopted the convention that is to mean the same as It is not the case that is true and false, brings out the important fact that this proposition is either identical with or logically equivalent to the proposition that of every such pair of propositions as