 Many of these masters concentrated on the logical curriculum, little changed since the late tenth century, but now its texts had been thoroughly absorbed. This curriculum gave them the opportunity, not just to make advances in what is still considered logic, but also to develop a whole metaphysics, starting not from Aristotle’s Metaphysics—which they did not know—but his Categories. The boldest of all these metaphysicians was  Peter Abelard  (1079–1142). Aristotle’s Categories seems to imply that, as well as particular substances (this man, that dog) and particular forms (this rationality, that whiteness), there are also universal substances and forms. Abelard did not agree, and he tried to construct the world and interpret Aristotle without admitting that any universals exist. He also attended to the ontological status of what sentences say—their dicta. Dicta play a central role in his understanding of truth and of the basis of logical consequence, but, he insists, they are not things at all. Gilbert of Poitiers (c. 1085–90–1154) constructed an even more complex metaphysical system, based on the distinction between types of discourse (natural, “mathematical”, theological, ethical).