William Crathorn - Ontology

Ontology

Crathorn differed from the standard system of Aristotle of categories. Crathorn felt the entire system had to be revised; the human mind naturally knows only qualities, and one cannot be certain that even they exist without appealing to the principle that God could not deceive us. Thinking and reasoning are of no help because they are purely conventional. For example, the category of substance is distinguished from the other categories by the fact that it has no contrary and can successively acquire contrary qualities. Thus, there are no non-substances, though a substance can be black and then white in succession, or cold and then gradually hot. But Crathorn claims that when we heat an object, not only the substance but also its qualities become hot, such that its qualities change from one state to their contrary exactly like a substance.