With the appearance of Thales as the first philosopher, the Greeks had come to have an inquiring mind (υου~ζ), that is, to be capable and fond of rational thought because he inquired into the first cause (α`ρχη`) or the primary substance (πρω~του υ`ποκει`μευου) and named it `water`(υ~δωρ).With this seeking and naming of his began the Western philosophy. That of Thales`, however, is not to be understood as an abrupt happening which might be entirely due to his genius, but as the result of some due causes. Probable causes might be many to enumerate. The present writer tried to trace the due causes and the rational way of thinking in its rudimentary stage. At the early stage, the autonomous, self-centered city-states (πο`λειζ) of Greece were monarchies, which began to be replaced throughout Greece by aristocracies in the ninth century before Christ. Homer was the spokesman of the then aristocrats. Those works of Homer`s, especially, the Iliad, which contains Greek myths and the glorious deeds of heroes (κλε`αα`υδρω~υ), has many aspects for us to study. As the spokesman of the nobles, he intended to rationalize the aristocrat class of the dominant power in the state as a corollary of the hierarchy of the Olympian gods. If we were to read Homer only in this respect, we might find him detestable. However, Homer was loved by numerous good men. The rise of Greek mythology, which appeared on a large scale in Homer`s works, means the end of magic and the beginning of a new phase in the Greek way of thinking, a step towards the rational way of thinking. With the abolishment of magic, the Greeks began to regard this world; not as malignant spirit-haunted, but as a stage on which the glorious deeds of men, the feats of brave heroes(τα`α´ριστει~α) were to be played. For the then Greeks manliness (α`υδρει`α) was the excellence orgoodness (α`ρετη`) of man. The manliness as α`ρετη` was replaced later by Hesiod`s `justice` (δι`κη), which implies the equality of all men. In the seventh century aristocracies began to be replaced by tyrannies. Ambitious, indignant individuals overthrew the aristocrat governments and made themselves tyrants (τυ`ραυυοι). They were successful and abolished class distinctions. The rise of tyranny brought the self-consciousness of individuality and equality. With this consciousness, individuals paid much attentions to their inner problems, and were going to enjoy the artistic and intellectual life, which was fostered by tyrants. Hence flourished lyric poetry instead of epic. People became susceptible individuals, and their sensitiveness induced them to feel the changeableness of nature and the vanities of life. Such a feeling became the very incentive for the Greeks to launch out into `the scientific research on physis` (περι` Φυ`σεωζΕστορι`η), that is, to seek something eternal. With such a social, political and intellectual background, Thales could come to the front as the first philosopher. But the research on physis alone did not suffice the inquiring mind of the Greeks. They undertook to study man in himself. Their research on man in himself gave birth to Greek tragedies and the study of α`ρετη` (the excellence or goodness of man) and υο`μοζ(the standard of ethics and knowledge). Greek tragedies, which date back to Thespis (539), culminated after the victory at the battle of Salamis (480), with which Athens became the school of Greece (`Eλλα`δοζ παι`δευσιζ). Greek tragedies dealt with the strange contradiction of man. The tragic poet intended to observe man in the utmost misery, poorness and man in the utmost grandeur. On the other hand the problem of α`ρετη` began to be dealt with by the Sophists and Socrates. Protagoras pretended himself to be `the teacher of arete` (α`ρετη~ζ διδα`σκαλοζ), while Socrates defined it. Later Plato and Aristotle "devised a