On Ideas

On Ideas (Greek: Περὶ Ἰδεῶν, Peri Ideōn) is a philosophical work which deals with the problem of universals with regards to Plato's Theory of Forms.

A point made in multiple places is that the Platonist arguments establish only that there are universals in a general and metaphysically slim sense, and not there are full-blown Forms of the Platonic kind.

However, the external evidence that On Ideas is an authentic work of Aristotle is ambiguous and its status as such is not universally recognized.

[2][3][4] The full Greek text of Alexander's commentary which includes On Ideas is published in the first volume of the Commentaria in Aristotelem Graeca.

Excerpts from this, along with an English translation and commentary by Gail Fine, are available in On Ideas: Aristotle's Criticism of Plato's Theory of Forms published by the Oxford University Press in 1993.