  This difference helps to explain why Buridan uses paradoxes of self-reference to test the functionality of his logic, whereas Ockham avoids them by claiming that a term—or at least a term in those circumstances—cannot refer to  itself.[10]  Buridan takes seriously the fact that people can and do utter self-referential propositions, and thinks logicians should say what is going on when they do. This is really a difference of perspective. As Joël Biard has pointed out, we can divide medieval logicians into those who try to restrict the possibilities of human discourse in the direction of what is logically ideal, and those who are willing to accept a proposition because it is grammatical and because the person who utters it intends to signify something by it. Ockham, William of Sherwood, and Walter Burley belong to the former group; Buridan and Thomas Bradwardine to the  latter.[11]  It also explains why Buridan tells us that it is not possible to analyze contradictory propositions unless they “have the same subject and predicate in utterance and also in intention” (S 9.7, 2nd sophism: 943), and his reminding us that, when testing a proposition for contradictoriness, “it is [sometimes] necessary to add other utterances when contradicting it…. For one should primarily attend to the intention, for we use words only to express the intention” (S 9.8, 11th sophism: 979). The logician must above all be a skilled interpreter of human discourse.