Since the beginning of time, man has found reasons for what made things and made things occur. For many centuries, the Greeks, Egyptians, and other early civilizations believed that the cause of these occurrences and events were gods, or divine intervention. However, the earliest philosophers, all from the port city of Miletus began to rationalize these occurrences. These philosophers, the earliest known, were Thales, Anaximander, and Anaximenes. They were the ones that triggered and asked all the questions that were later to be studied for thousands of years. These three believed that the world was comprised of four different elements: earth, fire, water, and air. However, they also believed that there was a source from which these elements came from. It was the force that drove and created everything in the universe, not the mythological gods. This force is what they referred to as the arche or the "first principle". Such principles were to be later seen in the Jewish, Christian, and Muslim religions. .
Thales, the earliest of the three, was the first to come to the realization that the gods could not be the driving force behind all of nature. He states, "All things are full of gods". Some have interpreted this as his observation of how everything from flowers and plants to animals comes from the black earth; he imagined that it was filled with invisible "life-germs", certainly not the mythological gods. Even if he was mentioning the mythological gods, he believed that they were simply a mechanism of the universe, not the authors of change. The Gods, dealing as they do with individual events in a changing world, are irrational. They cannot be a functioning part of a rational world. Thales believed that the driving force of change in the universe had to be one of the four elements. He believed that the source of all things is water, for it was water that gave life to the "life germs".