Also active in the city of Miletus was Anaximander, a student of Thales. Anaximander was one of the first philosophers to write a book. Like Thales, he was also interested in many different areas. He is attributed with the invention of the gnomon, although that is highly unlikely.
Anaximander was also thought to be the first to draw a map of the known world. He disagreed with his teacher regarding the basic substance of the universe. While Thales believed that everything came out of the water, Anaximander attributed everything to the Apeiron (literally translates as “the infinite”). This was an abstract entity that gave birth to everything and was the place where all things returned.&l