Abstract

The per se beings are those signified by the ultimate predicates in species–genus hierarchies: what a thing is, quality, quantity, relation, and so forth. Understanding change requires the investigation of the potential versus actual existence of any such per se being. Yu argues that Aristotle’s references in his central text on the focal structure of being to process, generation, and destruction imply that substance is the focus not only of the other per se beings but also of potential versus actual being. But, he holds, for different reasons, that the other per se beings depend on substance, whereas change in the category of substance raises the greatest difficulties for Parmenides’s argument against generation.