pre-eminent in the creation of science. Of these, Copernicus belongs to the sixteenth century,
but in his own time he had little influence.
Copernicus ( 1473-1543) was a Polish ecclesiastic, of unimpeachable orthodoxy. In his youth
he travelled in Italy, and absorbed something of the atmosphere of the Renaissance. In 1500 he
had a lectureship or professorship of mathematics in Rome, but in 1503 he returned to his
native land, where he was a canon of Frauenburg. Much of his time seems to have been spent in
combating the Germans and reforming the currency, but his leisure was devoted to astronomy.
He came early to believe that the sun is at the centre of the universe, and that the earth has a
twofold motion: a diurnal rotation, and an annual revolution about the sun. Fear of ecclesiastical
censure led him to delay publication of his views, though he allowed them to become known.
His chief work, De Revolutionibus Orbium CÅ“lestium, was published in the year of his death (
1543), with a preface by his friend Osiander saying that the heliocentric theory was only put
forward as a hypothesis. It is uncertain how far Copernicus sanctioned this statement, but the
question is not very important, as he himself made similar statements in the body of the book. *
The book is dedicated to the Pope, and escaped official Catholic condemnation until the time of
Galileo. The Church in the lifetime of Copernicus was more liberal than it became after the
Council of Trent, the Jesuits, and the revived Inquisition had done their work.
The atmospheze of Copernicus's work is not modern; it might rather be described as
Pythagorean. He takes it as axiomatic that all celestial motions must be circular and uniform,
and like the Greeks he allows himself to be influenced by æsthetic motives. There are still
epicycles in his system, though their centres are at the sun, or, rather, near the sun. The fact that
the sun is not exactly in the centre marred the simplicity of his theory. He does not seem to have
known of Aristarchus's heliocentric theory, but there is nothing in his speculations that could
not have occurred to a Greek astronomer. What was important in his work was the
dethronement of the earth from its geometrical pre-eminence. In the long run, this made it
difficult to give to man the cosmic importance assigned to him in the Christian theology, but
such consequences of his theory would not have been
* See Three Copernican Treatises, translated by Edward Rosen, Chicago, 1939.