We are but imperfectly acquainted with the life of Plato and the phases of his development, for the chronology of his dialogues has not been determined up to this time, either absolutely or relatively, and it is a matter of doubt how far their artistic intention admits of a complete exposition of his system. For Plato’s true work was not his literary productions, which he himself regarded as of secondary importance and which obviously reproduce only a fraction of his researches and speculations, but his Academy, in which, from the eighties of the fourth century onwards, he gathered together the ablest scholars from amongst the youth of Greece for study and life in community. If all the transactions of this Academy had been preserved (like the information Aristotle gives us concerning the latter years), it may be that we should be able to trace distinctly the development of this wonderful man. For Plato is both the most gifted and the most complicated personality of Greek antiquity, and the depths and recesses of his nature were not wholly penetrated by his intimate friends, not even by Aristotle; how much less by us of this latter day. What we do possess is, however, amply sufficient to indicate at least his place in this summary. If from the ranks of the Greek thinkers we have so far considered, we choose out the most eminent leaders and mark the lines of connection between them, we shall see how they all converge to Plato. He is the focus of ancient philosophy, whither all that went before him tends, and whence bright light and warmth stream forth upon posterity down to our own day. The range of his achievements alone is enough to make this evident. Like the Ionians his grasp embraces cosmology, physics, and anthropology. Like the Pythagoreans he pursues the study of mathematics with ever increasing devotion, presumably as the basis of his speculations. Like Xenophanes he enters the school of the ancient Orphic Mysticism, and in the _Timæus_ exalts it into a theology culminating in Monotheism. Like the Eleatics he ponders the problems of ontology. Like Heraclitus he inquires into the eternal flow of genesis; he ponders on the ideals of culture and the political theories of the Sophists, he wrestles with the ideal method of Socrates, he strives with hostile philosophers of the Socratic school on this hand and on that (Aristippus, Euclides, and Antisthenes), and, lastly, he strives with himself as his speculation develops more and more along theological and mathematical lines. For, as the genuine servant of Truth, Plato regards himself up to old age as in process of growing and learning. Nothing is so hateful to him as Dogmatism. Nevertheless there are so many opinions to which he held with unwavering constancy that we are probably justified in speaking of the system of Plato.