The history of philosophy is thus divided into three grand epochs. The first reaching from Thales to the time of Socrates (B.C. 639-469): the second from the birth of Socrates to the death of Aristotle (B.C. 469-322); the third from the death of Aristotle to the Christian era (B.C. 322, A.D. 1). Greek philosophy during the first period was almost exclusively a philosophy of nature; during the second period, a philosophy of mind; during the last period, a philosophy of life. Nature, man, and society complete the circle of thought. Successive systems, of course, overlap each other, both in the order of time and as subjects of human speculation; and the results of one epoch of thought are transmitted to and appropriated by another; but, in a general sense, the order of succession has been very much as here indicated. Setting aside minor schools and merely incidental discussions, and fixing our attention on the general aspects of each historic period, we shall discover that the first period was eminently _Physical_, the second _Psychological_, the last _Ethical_. Every stage of progress which reason, on _à priori_ grounds, would suggest as the natural order of thought, or of which the development of an individual mind would furnish an analogy, had a corresponding realization in the development of Grecian thought from the time of Thales to the Christian era. "Thought," says Cousin, "in the first trial of its strength is drawn without." The first object which engages the attention of the child is the outer world. He asks the "_how_" and "_why_" of all he sees. His reason urges him to seek an explanation of the universe. So it was in the _childhood_ of philosophy. The first essays of human thought were, almost without exception, discourses περὶ φύσεως (De rerum natura), of the nature of things. Then the rebound of baffled reason from the impenetrable bulwarks of the universe drove the mind back upon itself. If the youth can not interpret nature, he can at least "know himself," and find within himself the ground and reason of all existence. There are "_ideas_" in the human mind which are copies of those "_archetypal ideas_" which dwell in the Creative Mind, and after which the universe was built. If by "analysis" and "definition" these universal notions can be distinguished from that which is particular and contingent in the aggregate of human knowledge, then so much of eternal truth has been attained. The achievements of philosophic thought in this direction, during the Socratic age, have marked it as the most brilliant period in the history of philosophy--the period of its _youthful_ vigor. Deeply immersed in the practical concerns and conflicts of public life, _manhood_ is mainly occupied with questions of personal duty, and individual and social well-being. And so, during the hopeless turmoil of civil disturbance which marked the decline of national greatness in Grecian history, philosophy was chiefly occupied with questions of