Full Idea
Knowledge is a double thing, being both potential and actual. It is universal and indefinite and it is the potentiality of something that is universal and indefinite. But actuality is definite and of something definite, being the this-such of a this-such.
Clarification
'This-such' translates 'tode ti'
Gist of Idea
Knowledge of potential is universal and indefinite; of the actual it is definite and of individuals
Source
Aristotle (Metaphysics [c.324 BCE], 1087a12)
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.428
A Reaction
Charlotte Witt identifies this as a key idea in 'Metaphysics', since the metaphysics is built on the epistemology, and this idea justifies the claim that Aristotle gives priority to particulars. I thoroughly approve. Not all knowledge is of the universal.