Full Idea
It is impossible to define particulars. …The fact is that an account is general.
Gist of Idea
You can't define particulars, because accounts have to be generalised
Source
Aristotle (Metaphysics [c.324 BCE], 1040a33-)
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.224
A Reaction
Aristotle rejects attempts to define the Sun as possible counterexamples. Since this claims rests on the idea of an account [logos], I presume the point is actually that definitions are linguistic, and must use general words.