IX. GREEK SCIENCE OF THE ALEXANDRIAN OR HELLENISTIC PERIOD The
precise genesis and development of this idea cannot now be
followed, but that it was prevalent about the fifth century B.C.
as a Pythagorean doctrine cannot be questioned. Anaxagoras also
is said to have taken account of the hypothetical counter-earth
in his explanation of eclipses; though, as we have seen, he
probably did not accept that part of the doctrine which held the
earth to be a sphere. The names of Philolaus and Heraclides have
been linked with certain of these Pythagorean doctrines.
Eudoxus, too, who, like the others, lived in Asia Minor in the
fourth century B.C., was held to have made special studies of
the heavenly spheres and perhaps to have taught that the earth
moves. So, too, Nicetas must be named among those whom rumor
credited with having taught that the world is in motion. In a
word, the evidence, so far as we can garner it from the
remaining fragments, tends to show that all along, from the time
of the early Pythagoreans, the