Anaximander

Anaximander of Miletus (c. 610 – 546 BCE) was a pupil and successor of Thales and the first Greek thinker known to have written a prose treatise on nature. Where his teacher had named water as the source of all things, Anaximander looked for something that could not itself be one of the things it produced. He called it the apeiron, the boundless or indefinite: an inexhaustible stock of matter without any of the qualities that separate one element from another.

The boundless

The argument that survives is short but careful. If the source were water, water would eventually overwhelm fire, its opposite; if it were fire, the reverse. A source that is to persist through every change must stand outside the contest of opposites. From the boundless, hot and cold separate off, and from their interaction come the sea, the land and the heavens. The world we see is one outcome of that separation, and Anaximander is reported to have said there are countless others, arising and perishing in turn.

Justice among the elements

A single sentence of his is quoted by later writers, and it is usually taken to be the oldest surviving fragment of Western philosophy:

The things that are give recompense to one another for their injustice, according to the ordering of time.

The language is legal. Each element, in gaining ground, commits an offence against its opposite, and time exacts the penalty by returning the balance. Nature is not arbitrary; it is governed by a settled order of exchange, and the seasons are its most visible instance.

Other contributions

• He drew the first Greek map of the inhabited world, placing the known lands around the Mediterranean.
• He set up a gnomon at Sparta to mark the solstices and equinoxes.
• He held that the earth is a short cylinder floating unsupported at the centre of the cosmos, staying put because it has no reason to move one way rather than another.
• He proposed that the first living things arose in moisture and that human beings developed from fish-like ancestors, since a human infant could not have survived on its own.

Why he matters

Anaximander's importance is less in any single doctrine than in the shape of his reasoning. He replaced a named substance with an abstract principle, defended the choice by argument, and explained the observed world as the result of impersonal processes acting under a rule. That pattern, principle plus argument plus mechanism, is the pattern later Greek science kept.