Though Antisthenes and Diogenes laid chief stress upon ethical topics, yet they also delivered opinions on logic and evidence.[122] Antisthenes especially was engaged in controversy, and seemingly in acrimonious controversy, with Plato; whose opinions he impugned in an express dialogue entitled Sathon. Plato on his side attacked the opinions of Antisthenes, and spoke contemptuously of his intelligence, yet without formally naming him. At least there are some criticisms in the Platonic dialogues (especially in the Sophistês, p. 251) which the commentators pronounce, on strong grounds, to be aimed at Antisthenes: who is also unfavourably criticised by Aristotle. We know but little of the points which Antisthenes took up against Plato and still less of the reasons which he urged in support of them. Both he and Diogenes, however, are said to have declared express war against the Platonic theory of self-existent Ideas. The functions of general Concepts and general propositions, together with the importance of defining general terms, had been forcibly insisted on in the colloquies of Sokrates; and his disciple Plato built upon this foundation the memorable hypothesis of an aggregate of eternal, substantive realities, called Ideas or Forms, existing separate from the objects of sense, yet affording a certain participation in themselves to those objects: not discernible by sense, but only by the Reason or understanding. These bold creations of the Platonic fancy were repudiated by Antisthenes and Diogenes: who are both said to have declared "We see Man, and we see Horse; but Manness and Horseness we do not see". Whereunto Plato replied "You possess that eye by which Horse is seen: but you have not yet acquired that eye by which Horseness is seen".[123] [Footnote 122: Among the titles of the works of Antisthenes, preserved by Diogenes Laertius (vi. 15), several relate to dialectic or logic. [Greek: A)lê/theia. Peri\ tou= diale/gesthai, a)ntilogiko/s. Sa/thôn, peri\ tou= a)ntile/gein, a, b, g. Peri\ Diale/kton. Peri\ Paidei/as ê)\ o)noma/tôn, a, b, g, d, e. Peri\ o)noma/tôn chrêseôs, ê)\ e)ristiko/s. Peri\ e)rôtê/seôs kai\ a)pokri/seôs], &c., &c. Diogenes Laertius refers to _ten_ [Greek: to/moi] of these treatises.] [Footnote 123: Simplikius, ad Aristot. Categ. p. 66, b. 47, 67, b. 18, 68, b. 25, Schol. Brand.; Tzetzes, Chiliad. vii. 606. [Greek: tô=n de\ palaiô=n oi( me\n a)nê/|roun ta\s poio/têtas tele/ôs, to\ poio\n sugchôrou=ntos ei)=nai; ô(/sper A)ntisthe/nês, o(/s pote Pla/tôni diamphisbêtô=n--ô(= Pla/tôn, e)/phê, i(/ppon me\n o(rô=, i(ppo/têta d' ou)ch o(rô=; kai\ o(\s ei)=pen, e)/cheis me\n ô(=| i(/ppos o(ra=tai to/de to\ o)/mma, ô(=| de\ i(ppo/tês theôrei=tai, ou)de/pô ke/ktêsai. kai\ a)/lloi de/ tines ê)=san tau/tês tê=s do/xês. oi( de\ tina\s men a)nê/|roun poio/têtas, tina\s de\ kateli/mpanon]. [Greek: Anthrôpo/tês] occurs p. 58, a. 31. Compare p. 20, a. 2.