Even from the beginning, man has wanted to know why and how we exist. Pre-Socratic philosophers sought to find the basic principles of man. Thales was the first natural philosopher believed that water was the basic unit from which all things were made. Anaximander, who was a student of Thales, referred to the stuff from which all is made as the indefinite or apeiron. He also believed in the theory of evolution, meaning that humans came from other types of animals. A student of Anaximander was Anaximenes, and he refers to the basic stuff as still boundless, but not indefinite. He says it is aer or eather. He believed that even divine things would