  Unfortunately, this looks no less ad hoc than the transcasus and restriction solutions he has just criticized. Why shouldn't other propositions, besides the paradoxical ones, be able to signify that they are false? Buridan does not say in his commentary on the Posterior Analytics, and in the Summulae he rejects his earlier view for the rather different reason that it is false “that every proposition signifies or asserts itself to be true” (S 9.8, 7th sophism: 968). His argument is not exactly clear, but the problem appears to be semantic: he cannot find an interpretation of the phrase ‘itself to be true [se esse veram]’ in the supplementary condition that will permit it to function as a general principle. Consider the proposition ‘A man is an animal [homo est animal]’. If we understand it materially, i.e., as standing for a proposition, then it will signify ‘The proposition “A man is an animal” is true’, which is false because it refers to second intentions (concepts or signs by means of which we conceive of other concepts or signs as such), and the original proposition refers to things (human beings and animals), not concepts. But what if we say that a proposition signifies itself to be true if it is taken significatively for the things or first intentions, rather than materially? This will not work either, argues Buridan, because then the affirmative proposition ‘A man is a donkey [homo est asinus]’ would signify that a man is a donkey, which is false because the subject term ‘man’ does not supposit for anything (no human beings are  donkeys).[30]  Accordingly, we cannot base our solution to self-referential paradoxes on the idea that every proposition signifies or asserts itself to be  true.[31]