If however we suppose that Plato must have had the key present to his own mind, he might still think it right to employ, in such a dialogue, reasonings recognised by himself as defective. It is the task imposed upon Sokrates to find out and expose these defective links. There is no better way of illustrating how universal is the malady of human intelligence--unexamined belief and over-confident affirmation--as it stands proclaimed to be in the Platonic Apology. Sokrates is exhibited in the Parmenides as placed under the screw of the Elenchus, and no more able than others to extricate himself from it, when it is applied by Parmenides: though he bears up successfully against Zeno, and attracts to himself respectful compliments, even from the aged dialectician who tests him. After the Elenchus applied to himself, Sokrates receives a farther lesson from the "Neither and Both" demonstrations addressed by Parmenides to the still younger Aristotle. Sokrates will thus be driven, with his indefatigable ardour for speculative research, to work at the problem--to devote to it those seasons of concentrated meditation, which sometimes exhibited him fixed for hours in the same place and almost in the same attitude[58]--until he can extricate himself from such difficulties and contradictions. But that he shall not extricate himself without arduous mental effort, is the express intention of Parmenides: just as the Xenophontic Sokrates proceeds with the youthful Euthydemus and the Platonic Sokrates with Lysis, Theætetus, and others. Plausible subtlety was not unsuitable for such a lesson.[59] Moreover, in the Parmenides, Plato proclaims explicitly that the essential condition of the lesson is to be strictly private: that a process so roundabout and tortuous cannot be appreciated by ordinary persons, and would be unseemly before an audience.[60] He selects as respondent the youngest person in the company, one still younger than Sokrates: because (he says) such a person will reply with artless simplicity, to each question as the question may strike him--not carrying his mind forward to the ulterior questions for which his reply may furnish the handle--not afraid of being entangled in puzzling inconsistencies--not solicitous to baffle the purpose of the interrogator.[61] All this betokens the plan of the dialogue--to bring to light all those difficulties which do not present themselves except to a keen-sighted enquirer. [Footnote 58: Plato, Symposion, p. 220 C-D: compare pp. 174-175. In the dialogue Parmenides (p. 130 E), Parmenides himself is introduced as predicting that the youthful Sokrates will become more and more absorbed in philosophy as he advances in years. Proklus observes in his commentary on the dialogue--[Greek: o( ga\r Sôkra/tês a)/gatai ta\s a)pori/as], &c. (L. v. p. 252).] [Footnote 59: Xenoph. Memor. iv. 2, ad fin.]