This book describes how the Greeks were the first to establish philosophy and science, that is, the rational explanation of the world, the most distinctive and decisive event in the history of European thought.

The description and explanation of the process by which rational thought was born and began to develop in Greece and the world is a work of particular importance for philosophy, because wanting to provide a description of the pre-Socratic spirit is like wanting to describe the initial stages of the formation of modern philosophical thought.

The beginning of philosophy does not simply mean the start, the genetic act of philosophy, but also the source from which philosophy draws and is nourished in its later course of development.

The case of pre-Socratic thought constitutes the beginning of philosophy in both of these meanings: the pre-Socratic problematic is the beginning and womb, source and nourisher of the philosophical and scientific spirit.

In general, the development of proto-philosophical and proto-scientific thought in Greece demonstrates the critical capabilities and open spirit of the Greek city in contrast to the closed world of mythical tradition.