Full Idea
It takes expertise in dialectic to divide things by kinds and not to think that the same form is a different one or that a different form is the same.
Gist of Idea
Good analysis involves dividing things into appropriate forms without confusion
Source
Plato (The Sophist [c.358 BCE], 253d)
Book Reference
Plato: 'The Sophist', ed/tr. Bernadete,Seth [University of Chicago 1986], p.49