  Aristotle next draws a distinction between “signifying” and “signifying about”. The opponent needs to do both and not merely signify about. One can signify about something by saying “pale (thing)”, but that does not tell you what you are signifying, e.g., a human being. “Human being” both signifies about and signifies a human being. If “human being” means something definite, for example, “two-footed animal” (Aristotle’s dummy definition), then, Aristotle concludes, it is impossible that the same thing be a human being and not be a human being. (For a parallel discussion, see Posterior Analytics I 22.)