Perception, knowledge, and abstraction have the general structure of relations. Such abstract nouns as "perception" have the ambiguity that they can name both the relation and relata , as in "perception is the perception of something perceptible". Two paronymous relata can be derived from the abstract paronym : "perceiving as a state of movement of soul " and "what is being perceived" from "perception". When given in the same mode, like first actuality , these relata are simultaneous , although one may have causal priority over the other. There is a single relational complex, which can be described from the standpoint of either relata . These points hold for abstraction too.Like other relata , abstractions can be taken as subjects in their own right, despite depending on their substances for their existence. Aristotle treats the objects of science in the same way: they may be taken as if they are independent even though they are not. By treating universals and essences in this way, Aristotle can have a science of universals and still avoid Platonism .