Though the subject of direct debate in the Menon is the same as that in the Protagoras (whether virtue be teachable?) yet the manner of treating this subject is very different in the two. One point of difference between the two has been just noticed. Another difference is, that whereas in Menon the teachability of virtue is assumed to be disproved, because there are no recognised teachers or learners of it--in the Protagoras this argument is produced by Sokrates, but is combated at length (as we shall presently see) by a counter-argument on the part of the Sophists, without any rejoinder from Sokrates. Of this counter-argument no notice is taken in the Menon: although, if it be well-founded, it would have served Anytus no less than Protagoras, as a solution of the difficulties raised by Sokrates. Such diversity of handling and argumentative fertility, are characteristic of the Platonic procedure. I have already remarked, that the establishment of positive conclusions, capable of being severed from their premisses, registered in the memory, and used as principles for deduction--is foreign to the spirit of these Dialogues of Search. To settle a question and finish with it--to get rid of the debate, as if it were a troublesome temporary necessity--is not what Plato desires. His purpose is, to provoke the spirit of enquiry--to stimulate responsive efforts of the mind by a painful shock of exposed ignorance--and to open before it a multiplicity of new roads with varied points of view. [Side-note: Anxiety of Plato to keep up and enforce the spirit of research.] Nowhere in the Platonic writings is this provocative shock more vividly illustrated than in the Menon, by the simile of the electrical fish: a simile as striking as that of the magnet in Ion.[37] Nowhere, again, is the true character of the Sokratic intellect more clearly enunciated. "You complain, Menon, that I plunge your mind into nothing but doubt, and puzzle, and conscious ignorance. If I do this, it is only because my own mind is already in that same condition.[38] The only way out of it is, through joint dialectical colloquy and search; in which I invite you to accompany me, though I do not know when or where it will end." And then, for the purpose of justifying as well as encouraging such prolonged search, Sokrates proceeds to unfold his remarkable hypothesis--eternal pre-existence, boundless past experience, and omniscience, of the mind--identity of cognition with recognition, dependent on reminiscence. "Research or enquiry (said some) is fruitless. You must search either for that which you know, or for that which you do not know. The first is superfluous--the second impossible: for if you do not know what a thing is, how are you to be satisfied that the answer which you find is that which you are looking for? How can you distinguish a true solution from another which is untrue, but plausible?"