Milesian School of Philosophy

1. Milesian School

Pre-Socratic philosophy differs from all other philosophy in that it had no predecessors.

Philosophy has been a continuous debate, and even highly original thinkers can be seen developing from or reacting against the thought of a predecessor:

Aristotle is unimaginable without Plato; Isaac Newton, without René Descartes, Johannes Kepler, Galileo Galilei, and many others.

But with the Greeks of the 6th century BCE the debate begins:

Before them no European had set out to satisfy his curiosity about the world in the faith that its apparent chaos concealed a permanent and intelligible order, and that this natural order could be accounted for by universal causes operating within nature itself and discoverable by human reason.

They had predecessors of a sort, of course:

It was not accidental that the first pre-Socratics were citizens of Miletus, a prosperous trading centre of Ionian Greeks on the Asiatic coast, where Greek and Oriental cultures met and mingled.

The Milesian heritage included the myths and religious beliefs of their own people and their Eastern neighbours and also the store of Egyptian and Babylonian knowledge—astronomical, mathematical and technological.

The influence of this heritage was considerable:

Yet the Milesians consciously rejected the mythical and religious tradition of their ancestors, in particular its belief in the agency of anthropomorphic gods, and their debt to the knowledge of the East was not a philosophic one. That knowledge was limited because its aim was practical.

Astronomy served religion; mathematics settled questions of land measurement and taxation:

For these purposes the careful recording of data and the making of certain limited generalizations sufficed, and the realm of ultimate causes was left to dogmatism.

For the Greeks knowledge became an end in itself, and in the uninhibited atmosphere of Miletus they gave free play to the typically Greek talent for generalization, abstraction, and the erection of bold and all-embracing explanatory hypotheses.

Consciously, the revolt of the Milesian philosophers against both the content and the method of mythology was complete:

No longer were natural processes to be at the mercy of gods with human passions and unpredictable intentions. In their place was to come a reign of universal and discoverable law.

Yet a whole conceptual framework is not so easily changed:

Poetic and religious cosmogonies had preceded the schemes of the Milesians, and the basic assumptions of these can be detected beneath the hypotheses of their philosophic successors.

Nevertheless, the achievement of abandoning Divine agencies for physical causes working from within the world itself can hardly be overestimated:

It was common to the mythologies of Greece and neighbouring civilizations (and, indeed, to others) that the world arose from a primitive state of unity and that the cosmogonic process was one of separation or division.

2. Thales

It is not surprising, therefore, that the first people to seek a universal explanation of the world along rational lines assumed that it was in substance a unity from which its variety had been produced by some process of segregation:

The key, they thought, lay in identifying the single substance that must satisfy the condition of being able to produce variety out of itself.

Thales (active in 585 BCE), who chose Water or Moisture, may still have had the myths at the back of his mind. For him the earth floated on water as it did for the Egyptians.

Little else certain is known of him, and we can only guess at his reasons.

Water can be seen as solid, liquid, and vaporous:

Aristotle thought it more probable that Thales was influenced by the essential connection of moisture with life, as seen in such substances as semen, blood, and sap.

With the removal of external personal agents, the world must initiate its own changes, and at this early stage of speculation the only possibility seemed to be that life of some kind is everywhere and that the universe is a growing, organic structure:

This may be the explanation of the saying attributed to Thales: “Everything is full of gods.”

3. Anaximander

With Anaximander, Thales’ younger contemporary, there emerges the notion of the 4 primary opposites that later, when the concepts of substance and attribute had been distinguished, gave rise to the 4 elements adopted by Aristotle and destined for a long and influential history.

Anaximander spoke of only the hot and the dry, which were inevitably in conflict with the cold and the wet. This led him to a momentous idea:

The original substance of the universe could not be anything definitely qualified like water, for how could the cold and wet produce their opposites, the hot and dry?

Water quenches fire; it cannot engender it.

Prior to all perceptible body there must be an indefinite something with none of the incompatible qualities implied by perceptibility. Although still regarding all that exists as corporeal, Anaximander is the first to find ultimate reality in the non-perceptible.

This primary substance he called the Apeiron, a word of many meanings all related to the absence of limits— everlasting, infinite, indefinite.

Because it was imperishable, the origin of all things, and the author of their changes, he called it (says Aristotle) divine:

From it all things have been “separated out,” though in what sense they were previously “in” it while the Apeiron itself remained a unity is a question that probably did not present itself to him.

Somewhere in the Apeiron, Theophrastus asserts, a “germ” or “seed” of hot and cold was separated off, and from the interaction of these two flowed the whole cosmic process.

A sphere of flame enclosed a moist mass, more solid at the centre where the earth formed, vaporous between.

The sphere burst into rings around which the dark vapour closed, leaving holes through which we see what appear as sun, moon, and stars.

Wet and dry continue to separate, forming land and sea, and finally life itself is produced by the same action of heat (sun) on the cold and moist portions of the earth.

The first animals were born in water and crawled onto dry land.

Human infants were originally born and nurtured within the bodies of fishlike creatures, for under primitive conditions unprotected babies could not have survived.

Earth, a flat cylinder, hangs freely in space because of its equal distance from all parts of the spherical universe.

The sun is the same size as Earth:
Eclipses are caused by the closing of the holes in the vapour tubes of the sun and moon.

In this first of all attempts at a rational cosmogony and zoogony, the sudden freedom from mythical modes of thought is almost incredible.

4. Anaximenes

Further reflection led Anaximenes, the youngest member of the Milesian school, to a different conclusion about the primary substance: It was Air.

In its elusiveness and invisibility as atmospheric Air, it could almost match the Apeiron,

and, whereas Apeiron, once differentiated into a universe, could no longer be so called, Air could become hotter and colder, rarer and denser, and still remain the same substance.

Moreover, this theory allowed Anaximenes to break with the notion of separation, which was, at bottom, mythical, and account for the universe by the extension of a known natural process:

This was condensation and rarefaction,
the former of which he associated with cold and the latter with heat.

Air as it rarefies becomes fire;
condensed, it turns first to wind,
then to cloud, water, earth, and stones.

In other words, it is all a question of how much of it there is in a given space, and for the first time the idea enters science that qualitative differences are reducible to differences of quantity.

This is Anaximenes’ main achievement, although there is no evidence that he applied the principle with any mathematical exactness.

With Air as his basic, self-changing substance, Anaximenes could find room for the ancient belief that life was identical with breath.

Macrocosm and microcosm were animated by the same principle:

Just as our soul, which is Air, integrates us,
so breath and
Air surround the whole cosmos.”

The few details that we have of his cosmology suggest that compared with Anaximander’s, it was reactionary and timid. His contribution lies elsewhere.