This important proposition--That before a man can be entitled to lay down with confidence any affirmative theory, in the domain of philosophy or "reasoned truth," he must have had before him the various knots tied by negative dialectic, and must find out the way of untying them--is a postulate which lies at the bottom of Plato's Dialogues of Search, as I have remarked in the eighth chapter of this work. But there is much difference in the time, manner, and circumstances, under which such knots are brought before the student for solution. In the Parmenidês the process is presented as one both serious and indispensable, yet requiring some precautions: the public must be excluded, for they do not understand the purpose: and the student under examination must be one who is competent or more than competent to bear the heavy burthen put upon him, as Sokrates is represented to be in the Parmenidês.[18] In the Euthydêmus, on the contrary, the process is intended to be made ridiculous; accordingly these precautions are disregarded. The crowd of indiscriminate auditors are not only present, but are the persons whose feelings the two Sophists address--and who either admire what is said as dexterous legerdemain, or laugh at the interchange of thrusts, as the duel becomes warmer: in fact, the debate ends with general mirth, in which the couple themselves are among the loudest.[19] Lastly, Kleinias, the youth under interrogation, is a modest novice; not represented, like Lysis in the dialogue just reviewed, as in danger of corruption from the exorbitant flatteries of an Erastes, nor as requiring a lowering medicine to be administered by a judicious friend. When the Xenophontic (historical) Sokrates cross-examines and humiliates Euthydêmus (a youth, but nevertheless more advanced than Kleinias in the Platonic Euthydêmus is represented to be), we shall see that he not only lays a train for the process by antecedent suggestions, but takes especial care to attack Euthydêmus when alone.[20] The cross-examination pursued by Sokrates inflicts upon this accomplished young man the severest distress and humiliation, and would have been utterly intolerable, if there had been by-standers clapping their hands (as we read in the Platonic Euthydêmus) whenever the respondent was driven into a corner. We see that it was hardly tolerable even when the respondent was alone with Sokrates; for though Euthydêmus bore up against the temporary suffering, cultivated the society of Sokrates, and was handled by him more gently afterwards; yet there were many other youths whom Sokrates cross-examined in the same way, and who suffered so much humiliation from the first solitary colloquy, that they never again came near him (so Xenophon expressly tells us)[21] for a second. This is quite enough to show us how important is the injunction delivered in the Platonic Parmenidês--to carry on these testing colloquies apart from indiscriminate auditors,