calls him, Nicolaus Copernicus, as scholars call him, was born in 1473
at Thorn (Torun) on the Vistula in West Prussia, which, seven years
before, had been ceded to Poland by the Teutonic Knights; he was a
Prussian in space, a Pole in time. His mother came of a prosperous
Prussian family; his father hailed from Cracow, settled in Thorn,
and dealt in copper. When the father died (1483), the mother's
brother, Lucas Watzelrode, Prince Bishop of Ermland, took charge of
the children. Nicolaus was sent at eighteen to the University of
Cracow to prepare for the priesthood. Not liking the Scholasticism
that had there suppressed humanism, he persuaded his uncle to let
him study in Italy. The uncle had him appointed a canon of the
cathedral at Frauenburg in Polish East Prussia, and gave him leave
of absence for three years. *06069
At the University of Bologna (1497-1500) Copernicus studied
mathematics, physics, and astronomy. One of his teachers, Domenico
de Novara, once a pupil of Regiomontanus, criticized the Ptolemaic
system as absurdly complex, and introduced his students to ancient
Greek astronomers who had questioned the immobility and central
position of the earth. Philolaus the Pythagorean, in the fifth century
before Christ, had held that the earth and the other planets moved
around Hestia, a central fire invisible to us because all known
parts of the earth are turned away from it. Cicero quoted Hicetas of
Syracuse, also of the fifth century before Christ, as believing that
the sun, the moon, and the stars stood still, and that their
apparent motion was due to the axial rotation of the earth. Archimedes
and Plutarch reported that Aristarchus of Samos (310-230 B.C.) had
suggested the revolution of the earth around the sun, had been accused
of impiety, and had withdrawn the suggestion. According to Plutarch,
Seleucus of Babylonia had revived the idea in the second century
before Christ. This heliocentric view might have triumphed in
antiquity had not Claudius Ptolemy of Alexandria, in the second
century of our era, restated the geocentric theory with such force and
learning that hardly anyone thereafter dared to challenge it.
Ptolemy himself had ruled that in seeking to explain phenomena,
science should adopt the simplest possible hypothesis consistent
with accepted observations. Yet Ptolemy, like Hipparchus before him,
to explain the apparent motion of the planets, had been compelled by