From the Beginning to Plato

THE IONIANS 43
for it to be unreasonable to press doubts about the truth of the picture they
convey. These two thinkers were evidently fascinated with measurement, and
with the idea of putting to nature— and more especially the heavens—questions
which instruments could be employed to answer. 3
One other scientific puzzle (as we might now term it) which Thales is reported
to have tried to solve is the behaviour of the magnet. Here his style of enquiry
was very different. He claimed that magnets have soul: they have the power of
moving other bodies without themselves being moved by anything—but that is a
characteristic only of things that have soul, i.e. are alive. Heady speculation, not
ingenious observation, is now the order of the day. Perhaps the phenomenon of
magnetism was presented as one piece of evidence for the more general thesis,
‘All things are full of gods’, which Aristotle at any rate is inclined to interpret in
terms of the proposition that there is soul in the universe (i.e. not just in
animals). 4
In cosmological speculation Thales is presented by Aristotle as a champion of
the primacy of water as an explanatory principle. Aristotle writes as though
Thales meant by this that water was the material substrate of everything that
exists. But the authority on whom he relies for his information, the sophist
Hippias of Elis, seems to have mentioned Thales’ view in the context of a survey
of opinions about the origin of things. With one exception, to be discussed at
length shortly, Aristotle knows nothing else about the water principle. He
contents himself with the guess that Thales opted for it because warmth, sperm,
nutriment and the life they foster or represent are all functions of moisture. 5
The most definite claim Aristotle makes in this connection appears in On the
Heavens (II. 13, 294a28–32 [KRS 84]).
Others say that the earth rests on water. For this is the most ancient
account we have received, which they say was given by Thales the
Milesian, that it stays put through floating like a log or some other such
thing.
To come to terms with this unappealing version of flat-earthism we need to
consider two pieces of information relating to Thales’ intellectual grandchild
Anaximenes, pupil of Anaximander, both also of Miletus:
Anaximenes and Anaxagoras and Democritus say that its [the earth’s]
flatness is responsible for it staying put: for it does not cut the air beneath
but covers it like a lid, which is evidently what those bodies characterized
by flatness do.
(Aristotle On the Heavens II.13, 294b13ff. [KRS 150])
The earth is flat, riding upon air; and similarly also sun, moon and the
other stars, although they are all fiery, ride upon air on account of their
flatness.