On this account the oldest and most natural form of philosophy was that of dialogue, which did not, however, exclude the occasional introduction of a simple narrative, or the continuous explanation of higher and abstruser questions. Philosophy, accordingly, might not inappropriately be defined as a dialogue of the soul in its free meditation on divine things. And this was the very form it actually possessed among the earliest and noblest of the philosophers of antiquity--first of all really and orally, as with Pythagoras and Socrates, and lastly in its written exposition, of which style Plato was the great and consummate master. But it was only to the noblest and best of all ranks, though without distinction of age or sex, that these the greatest men of antiquity communicated their treasures of philosophical wisdom. In this course Pythagoras first set the example, which, on the whole, was followed also by Socrates and Plato. For, in general, the latter confined their philosophical teaching to a select circle, and imparted it, as it were, under the seal of friendship, to such only as in the social intercourse of life they admitted to close and familiar intimacy. Occasional exceptions were, perhaps, furnished by their disputes with the sophists, in the course of which they were constrained to adopt, not only the weapons, but also the method of their adversaries--a license of which Plato, perhaps, has too often availed himself, even if he has not sometimes abused it. For about this time the sophists introduced a practice as erroneous as their doctrine was false. Publishing their philosophemes to the whole people, they treated it and quarreled about it in the market-place as a common party matter. Such a procedure was in every sense pernicious, and one which must have brought even truth itself into contempt. Lastly, Aristotle comprised in his manuals the collective results of all earlier philosophical speculation, and intrusted his treasury of mature knowledge and well-sifted and newly-arranged thoughts to the keeping of a school. Now, we should be far from justified were we to make this a reproach against this master of subtlety and profoundest of thinkers; for at this time all true intellectual life had, together with public spirit, become extinct among the Greeks, amid the disorders of democracy, or under the pressure of the armed supremacy of Macedonia. Still it must ever remain a matter of profound regret. For philosophy, as standing in the center between the guiding spirit of the divine education of man and the external force of civil right and material power, ought to be true mundane soul [_Weltseele_] which animates and directs the development of ages and of the whole human race. Deeply, therefore, is it to be deplored whenever science, and especially philosophy, are withdrawn from this wide sphere of universal operation, and from human life itself, to remain banished and cooped up in the narrow limits of a school. LECTURE IV.