As an inevitable result of the Sceptical and Eclectic tendencies of the
age, the natural and mathematical sciences gradually broke loose from
philosophy. They flourished especially in the Greek islands of the
Mediterranean and in Egypt, because there they were free from the
disheartening influences which at Athens
and elsewhere in Hellas led to the dissolution of classical culture
and classical philosophy.
In Sicily, where the Pythagorean tradition was still unbroken,
Hicetas and Archimedes taught, as early as the third
century before Christ, a system of astronomy which was far superior to
the astronomical doctrines of Plato and Aristotle.  About the same
time Aristarchus of Samos advanced the hypothesis that the earth
moves round the sun. This theory was stamped as impious by the Stoics
and rejected by Ptolemy himself; it did not succeed in supplanting the
old conception until the dawn of modern times, when its truth was
demonstrated by Copernicus, Kepler, and Galileo.
 Cf. Cicero, Acad., XXXIX.
At Alexandria there developed under the influence of the Ptolemies a
new phase of philosophic thought, the study of which belongs to the
history of Greco-Oriental philosophy. Side by side with this new
philosophy there grew up a new science, of which Euclid (about 300
B.C.) is the chief representative. He wrote the Elements of
Geometry and treatises on Harmony, Optics, and
Catoptrics. Ptolemy (Claudius Ptolemaeus), who lived
about the middle of the second century after Christ, belongs also to
the Alexandrian school of science. His work, the Almagest, or
megalÍ suntaxis continued to be the authoritative source
of astronomical learning until the time of Copernicus.