Anaximander of Miletus

(c. 610-547/6 BC) The first Greek philosopher and astronomer whose thought is known in any detail. Anaximander constructed the first precise geometrical model of the universe, and produced maps of both the earth and the heavens. His inventions included the gnomon or upright pointer of the sundial used for tracking hours and seasons. Philosophically he is remembered for the quasi-theological conception of the apeiron or the boundless, limitless, imperishable, and eternal surrounding, which is also the archē or beginning of the cosmological process. The conception is an improvement on the cosmology of Thales, in that Anaximander sees that the attempt to find one kind of matter, out of which everything else in all its variety is made, must end not with water or fire or some other particular kind of matter, but with something independent of both structure and form: something about which nothing can be said. Out of the apeiron worlds are produced by a conflict of opposites, itself an ‘injustice’ for which things pay restitution to one another.