The Parmenides announces its own purpose as intended to repress premature forwardness of affirmation, in a young philosophical aspirant: who, with meritorious eagerness in the search for truth, and with his eyes turned in the right direction to look for it--has nevertheless not fully estimated the obstructions besetting his path, nor exercised himself in the efforts necessary to overcome them. By a curious transposition, or perhaps from deference on Plato's part to the Hellenic sentiment of Nemesis,--Sokrates, who in most Platonic dialogues stands forward as the privileged censor and victorious opponent, is here the juvenile defendant under censorship by a superior. It is the veteran Parmenides of Elea who, while commending the speculative impulse and promise of Sokrates, impresses upon him at the same time that the theory which he had advanced--the self-existence, the separate and substantive nature, of Ideas--stands exposed to many grave objections, which he (Sokrates) has not considered and cannot meet. So far, Parmenides performs towards Sokrates the same process of cross-examining refutation as Sokrates himself applies to Theætêtus and other young men elsewhere. But we find in this dialogue something ulterior and even peculiar. Having warned Sokrates that his intellectual training has not yet been carried to a point commensurate with the earnestness of his aspirations--Parmenides proceeds to describe to him what exercises he ought to go through, in order to guard himself against premature assertion or hasty partiality. Moreover, Parmenides not only indicates in general terms what ought to be done, but illustrates it by giving a specimen of such exercise, on a topic chosen by himself. [Side-note: Circumstances and persons of the Parmenides.] Passing over the dramatic introduction[1] whereby the personages discoursing are brought together, we find Sokrates, Parmenides, and the Eleatic Zeno (the disciple of Parmenides), engaged in the main dialogue. When Parmenides begins his illustrative exercise, a person named Aristotle (afterwards one of the Thirty oligarchs at Athens), still younger than Sokrates, is made to serve as respondent.