=The Waning of the Greek National Spirit.= The Systematic Period extends from the death of Socrates to the death of Aristotle. It is only seventy-seven years long――about the same length as the Anthropological and half as long as the Cosmological Period. It begins with those sorry days after the Peloponnesian War and ends with the supremacy of Macedonian power. The period was filled with ferocious wars among the Grecian cities. First came the supremacy of Sparta, then of Thebes (371–362 B. C.), then the invasion by Philip of Macedon and the battle of Chæronea, 338 B. C. In 334 B. C. Alexander the Great began the conquest of the Orient, which he accomplished in two years. He thought by this that he could reunite the Greeks in a common cause. He failed for two reasons. In the first place, as a Macedonian the Greeks would not take him as a national representative. In the second place, the Greek spirit was waning. The people had lost their glorious ideals. Decay had set in. The worm was at the root of Greek life. Greek art, literature, and statesmanship had passed. =The Place of the Three Systematic Philosophers in Greek History.= Nevertheless, when Greek national life was approaching dissolution, science ripened its richest fruits and created its most comprehensive systems of philosophy. These are connected with the names of Democritus, Plato, and Aristotle. These great systems evidently cannot be accounted for by the social conditions in which they appear. Neither the need nor the demand of the disrupted Greece of these years would be a sufficient cause to explain the appearance of a Plato or an Aristotle. The interests of the Greek people became narrower as the interests of the Greek philosophers became more broadly human. The intellectual tendency of this short period was utilitarian and practical. The problems that now interested the Athenians were the details of mechanics, physiology, rhetoric, and politics. The field of science was now for the first time systematized to logic, ethics, and physics――a classification which, we shall find, will exist for many centuries. Sparta and Macedonia, not Athens and Abdera, represent the spirit of the period.