The criticism of methods of thinking and methods of government was carried on after Plato’s death by Aristotle, who had been his pupil and who taught in the Lyceum. Aristotle came from the city of Stagira in Macedonia, and his father was court physician to the Macedonian king. For a time Aristotle was tutor to Alexander, the king’s son, who was destined to achieve very great things of which we shall soon be telling. Aristotle’s work upon methods of thinking carried the science of Logic to a level at which it remained for fifteen hundred years or more, until the mediæval schoolmen took up the ancient questions again. He made no Utopias. Before man could really control his destiny as Plato taught, Aristotle perceived that he needed far more knowledge and far more accurate knowledge than he possessed. And so Aristotle began that systematic collection of knowledge which nowadays we call Science. He sent out explorers to collect _facts_. He was the father of natural history. He was the founder of political science. His students at the Lyceum examined and compared the constitutions of 158 different states .... Here in the fourth century B.C. we find men who are practically “modern thinkers.” The child-like, dream-like methods of primitive thought had given way to a disciplined and critical attack upon the problems of life. The weird and monstrous symbolism and imagery of the gods and god monsters, and all the taboos and awes and restraints that have hitherto encumbered thinking are here completely set aside. Free, exact and systematic thinking has begun. The fresh and unencumbered mind of these newcomers out of the northern forests has thrust itself into the mysteries of the temple and let the daylight in. XXVI THE EMPIRE OF ALEXANDER THE GREAT From 431 to 404 B.C. the Peloponnesian War wasted Greece. Meanwhile to the north of Greece, the kindred country of Macedonia was rising slowly to power and civilization. The Macedonians spoke a language closely akin to Greek, and on several occasions Macedonian competitors had taken part in the Olympic games. In 359 B.C. a man of very great abilities and ambition became king of this little country—Philip. Philip had previously been a hostage in Greece; he had had a thoroughly Greek education and he was probably aware of the ideas of Herodotus—which had also been developed by the philosopher Isocrates—of a possible conquest of Asia by a consolidated Greece.