Full Idea
If there are Forms (as the purely logical thinkers claim), there must be something which is much more knowable than the Form of Knowledge, and something more fully moved than the Form of Movement. The Forms will be mere potentialities.
Gist of Idea
The Forms have to be potentialities, not actual knowledge or movement
Source
Aristotle (Metaphysics [c.324 BCE], 1050b32)
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.276