In the fifth and sixth centuries before Christ, people in Greece begin to think in a new way about the origins and primal causes of the world. We regard this thought today as representing an initial form of philosophizing. It was only hesitantly that it freed itself from its traditional ties to mythology, in which the genesis of the world is conceived of as a theogony. In the process, however, it laid its own foundations, on which our thinking is still based today. This also involves increasingly viewing the divine foundation of the world as a natural foundation, and identifying within it the foundations of our own thinking. This account rethinks the beginnings of philosophical thought on the basis of its own presuppositions. It traces developments from Thales to Democritus and places them in relation to each other. One difficulty with this process is that later thought has been superimposed on the initial stages, so that the views of the so-called ?Pre-Socratics= have been transmitted in only a fragmentary and patchy way.