Anaximenes of Miletus | Milesian school


Anaximenes of Miletus
 (c. 585 – c. 528 BCE)

Anaximenes was the 3rd and last member (the others were Thales and Anaximander) of what is traditionally called the Milesian school of natural philosophers.

Although little is known about his life and work, fragments of ancient testimony credit him with studies under his older contemporary, Anaximander; with the writing of a book in “simple Ionic”;

and with the doctrine that Air is the underlying principle of the universe, changes in physical state being the result of its condensation and rarefaction.

It is likely that Aristotle read Anaximenes’ book and that Theophrastus had access to it.

Several of the doxographers (Aetius, Hippolytus, Diogenes Laertius) may have read later Hellenistic versions of the work.

On the strength of ancient testimony, historians of philosophy after Aristotle regarded Anaximenes’ doctrine as a contribution to the Milesian debates on Nature:

They assumed that from Thales to Anaximenes there was a continuous development in physical thought, and they insisted that this development was intelligible only in terms of the supposedly unique problem of the period:

the birth and structure of the physical world.

On this interpretation, Anaximenes’ Air was taken to be an archē, and his condensation-rarefaction doctrine was construed as a theory about physical transformations.

The physical system reconstructed along these lines was then usually shown to be, in comparison with that of Anaximander, not as cogent; and whatever could not be accommodated within such a reconstruction was relegated to Anaximenes’ “retrogressive astronomy.”

Recent studies in mythical and early cosmogonic discourse (Hesiod) perhaps call for some revision of the traditional estimate:

At a time -

- when mechanical change and biological growth had not yet been distinguished from each other,

- when physical permanence was regarded as incomprehensible apart from “justice” between the warring Opposites,

- when inanimate continuity was mistaken for animal kinship,  
- when experience was permitted only to illustrate but never to refute supposed insight,  
- when meteorology served as the foundation for astrophysics—

- several of Anaximenes’ ideas were pioneering.

A schematic reconstruction of some of these ideas follows.

The fundamental and most pervasive thing in the world is Air, according to Anaximenes. Air is infinitely vast in extent but perfectly determinate in character:

It is ordinary atmospheric air, invisible where most even in consistency, visible through the Hot and Cold and Damp and motion.

It is from Air that all the things that exist, have existed, or will exist come into being:

This applies to gods and divine things and also to the rest of the world, inasmuch as the world is compounded out of the offspring of air.

On this account, Anaximenes suggests, the primordial Air is continually in motion, and this motion is the cause of alternating physical states.

Condensation and Rarefaction are the key manifestations of changing air:

Rarefied Air generates fire; condensed air creates winds; condensed winds, clouds; condensed clouds, water; condensed water, earth; earth, stones and the rest of the world.

Throughout the process of cosmic change, the Hot and the Cold are dominant states of physical activity, but in no way are they forces distinct from Air:

They never come out of Air by “separating off”; rather, they are “attributes” of Air when it condenses through “felting” or is rarefied through “loosening up.”

From the genesis of the universe at large, Anaximenes moves to the description of the shape of Earth and of the visible sky:

Earth, according to him, is broad, flat, and shallow—table-like.

All the heavenly bodies are fires in the sky, caused by the moist exhalations of Earth:

The heavenly bodies are nailed on a hemispherical diaphanous membrane and move around Earth like a cap that can be turned around one’s head, and not under Earth.

The stars do not produce any sensible heat because of their distance.

When the sun, moon, and stars disappear, they are hidden by the distant elevations of Earth.

The stars may also be likened to fiery leaves floating on the air.

Clouds, rain, hail, and snow—all these phenomena, too, are caused by Condensed Air. And the same is true of the violent breaks of the clouds that produce lightning and thunder.

With the elements of his cosmology worked out, Anaximenes seems to need a general natural law guaranteeing the regularity of the world:

He observes that as our souls, being Air (according to an ancient tradition), hold us together, so does the cosmic Air hold the world together by enclosing it.

Presumably what Anaximenes meant by this was that the regularity of an animated world is reliable and intelligible, as is the regularity of an animated body, a body that is organically self-regulative and autonomous—a microcosm.

For Anaximenes, law-like regularities were inconceivable without access to the idea of cause:

The notion of physical constraint was accordingly effected through containment. The Divine Air, by encasing the world, successfully regulates it.