Full Idea
It is a certain notion of understanding and, correspondingly, explanation which makes Aristotle think that knowledge, properly speaking, could not be a matter of mere experience.
Gist of Idea
Aristotle's concepts of understanding and explanation mean he is not a pure empiricist
Source
report of Aristotle (Posterior Analytics [c.327 BCE]) by Michael Frede - Aristotle's Rationalism p.160
Book Reference
'Rationality in Greek Thought', ed/tr. Frede,M /Striker,G [OUP 1999], p.160
A Reaction
Frede says this means that Aristotle is a rationalist, though few empiricists think understanding is 'merely' a matter of experience. My own epistemology is Explanatory Empiricism, which I see as more empiricist than rationalist.