Anaximander (approx. 610–546 BCE) was a pre-Socratic philosopher of ancient Greece. He was a student of Thales, who is considered by many to be the earliest Greek philosopher.
Like Thales before him, and Anaximenes, he belonged to the Milesean school at Miletus, Ionia on Asia Minor.
Like Thales, Anaximander sought to explain nature without reference to Greek mythology. Whereas Thales sought to explain the universe as originating from water, or moisture, which at light densities became air and could condense into rock, Anaximander envisioned a cyclic process. For him, the world was a balance of the opposing forces of cold and warm, wet and dry.
Anaximander argued that the world behaved like a human society, according to laws. These laws ensured that any significant disharmony would not last long, as the laws balanced out all of nature.
Remarkably, Anaximander was the first philosopher to attempt a completely naturalist, mechanistic model of the universe. He envisioned the earth as situated in the centre of apeiron. Originally, all that was this apeiron, an infinite (boundless) and undifferentiated mass in which a seed of the world formed. Gradually, the aperion would form around this seed and the world grew.
Anaximander said that the world was in the center of the universe, and it was for this reason that the land and the ocean did not fall. Rather, being in this location, the world could have no preference as to which direction it moved in.
Anaximander also suspected from evidence he found that human beings developed from earlier life forms, specifically fish.
Name: Αναξιμανδρος (Anaximandros / Anaximander)
Born: ~610 BCE
Died: ~546 BCE