The Early Greeks Man is naturally a philosopher. Brought face to face with the wonders of nature or the results of human endeavor, he is not content merely to observe the phenomena as they are offered to his senses, but feels impelled by his natural thirst for knowledge to investigate the causes through which these phenomena were produced. In this sense the story of philosophy is, as it were, lost and confused with the history of man. By philosophy we mean, however, nor any haphazard explanation of prime causes but intelligent and reflective research into the realities of things such as will justify the position of first causes from which arise the phenomena of life.
Reflective thought begins when the period of spontaneity closes.
Reflective thought needs spontaneous thinking as its starting point. Not satisfied with the elementary explanations which first intuition offers, the mind seeks to reconstruct the whole process of its labors on a new basis, the basis of reasoning. Thus Greek philosophy, which, as a product of reflective thought, begins in the sixth century before Christ with the philosophers of Miletus, presupposes another period. We might call it the early philosophic period, a period in which the proposed systems are a product more of the imagination than of reason. The first stage of this period preceding philosophy of which we have knowledge is that of universal animism.