transformations. It is in a sense a materialistic cosmology. But Anaximenes does not conceive of his air
as an inert substance which needs something else to set it in motion. He regards movement as an
intrinsic property of air. It is, as it were, a live substance, and the parallel he draws between the cosmic
air and the human soul implies an assumption that certainly became general in the fifth century, namely
that the soul is not something apart from the material world but a natural part of it. It is tempting to see
here an affinity with the Upanishadic doctrine of a universal wind or breath with which both the
unchanging life-soul of the world and the individual self are identical, by which living things and worlds
are held together, and which the whole universe obeys. Two details in Anaximenes' system which do not
suit it very well, the dark bodies that cause eclipses and the notion that the heavenly luminaries circle
round a great mountain in the north, seem to be of Iranian provenance.
The Milesians were unable completely to free themselves from the preconceptions of the myth-makers
of the pre-philosophical age. Like them, they assumed that something so complex as the present world
must have originated from something simple; that the earth is finite in extent and more or less circular,
with something different underneath it; that the sky is a physical entity at a definite distance from the
earth; that there are immortal sources of energy which are the moving or directing forces in the universe.
Their new, philosophical assumptions were that these forces operate in a perfectly consistent way that
can be observed in everyday phenomena; that everything can thus be explained from the working of a
few universal processes in a single original continuum; and that there is no such thing as creation from
nothing or decay to nothing, only change of substance. They tried to account systematically for all the
most notable features of the world about us: the movements of the heavenly bodies, phases of the moon,
eclipses; lightning, thunder, rain, snow, hail, rainbows, earthquakes, the annual inundation of the Nile.
One thinker who did succeed in breaking right away from conventional world models was Xenophanes.
His independence of mind took him in a direction so contrary to the truth that he gets little but derision
from modern writers; yet no one else so ruthlessly followed the rule of measuring the unseen by the
seen. What he saw was earth stretching in all directions, with empty air above it. He accordingly
declared that the earth was of infinite length, breadth, and depth, and that the air extended infinitely
upwards. The disappearance of the sun and other luminaries beyond the western horizon he explained as
an optical illusion: they were really continuing in a straight line, just getting further away. The sun that
arrives in the east the next morning is a different one. There are, moreover, other suns and moons
moving on parallel tracks over other regions of the earth, because the rising vapours form clouds which
become incandescent, and this happens with strict regularity.
His theology also was radical, without being so eccentric. He was certainly not the first to reject the idea
of gods having human shape or behaving as immorally as they do in Homer, but it was he who pointed
out that the Thracians represent the gods as like Thracians, the Negroes as negroid, and if cows and
horses had hands they -would no doubt depict their gods as cows and horses. The late sixth to the early
fifth century was a time when the Greeks were developing a particular interest in the beliefs and customs
of other nations. As Xenophanes' argument illustrates, the effect was to make them aware how much
their own beliefs and customs were based on mere convention, which might profitably be challenged.
Xenophanes' god is equally suitable for Thracians or cows. He does not have eyes or ears: every part of
him is sentient. He does not go about from place to place but stays still, effortlessly moving everything