And as Aristotle is the inventor of the treatise, so the Platonic Dialogue, in its conception, its peculiar opportunities, is essentially an essay--an essay, now and then passing into the earlier form of philosophic poetry, the prose-poem of Heraclitus. There have been effective writers of dialogue since, Bruno, for instance, Berkeley, Landor, with whom, however, that literary form has had no strictly constitutional propriety to the kind of matter it conveyed, as lending itself (that is to say) structurally to a many-sided but hesitant consciousness of the truth. Thus, with Berkeley, its purpose is but to give a popular turn to certain very dogmatic opinions, about which there is no diffidence, there are no half-lights, in the writer's own mind. With Plato, on the other hand, with Plato least of all is the dialogue--that peculiar modification of the essay--anything less than essential, necessary, organic: the very form belongs to, is of the organism of, the matter which it embodies. For Plato's Dialogues, in fact, reflect, they refine [177] upon while they fulfil, they idealise, the actual method, in which, by preference to anything like formal lecturing (the lecture being, so to speak, a treatise in embryo) Socrates conveyed his doctrine to others. We see him in those Dialogues of Plato, still loitering in the public places, the open houses, the suburban roads, of Athens, as if seeking truth from others; seeking it, doubtless, from himself, but along with, and by the help of, his supposed scholars, for whom, indeed, he can but bring their own native conceptions of truth to the birth; but always faithfully registering just so much light as is given, and, so to speak, never concluding. The Platonic Dialogue is the literary transformation, in a word, of what was the intimately home-grown method of Socrates, not only of conveying truth to others, but of coming by it for himself. The essence of that method, of "dialectic" in all its forms, as its very name denotes, is dialogue, the habit of seeking truth by means of question and answer, primarily with one's self. Just there, lies the validity of the method--in a dialogue, an endless dialogue, with one's self; a dialogue concerning those first principles, or "universal definitions," or notions, those "ideas," which, according to Plato, are the proper objects of all real knowledge; concerning the adequacy of one's hold upon them; the relationship to them of other notions; the plausible conjectures in our own or other minds, [178] which come short of them; the elimination, by their mere presence in the mind, of positive ignorance or error. Justice, Beauty, Perfect Polity, and the like, in outlines of eternal and absolute certainty:--they were to be apprehended by "dialectic," literally, by a method (methodos)+ a circuitous journey, presented by the Platonic dialogues in its most accomplished literary form.