matter whether they be true, even approximately, or not, so long as
they enable us to compute tables from which the places of the planets
among the stars can be predicted.[9] He says that whoever is not
satisfied with this explanation must be contented by being told that
"mathematics are for mathematicians" (Mathematicis mathematica
scribuntur).

At the same time he expresses his conviction over and over again that
the earth is in motion. It is with him a pious belief, just as it was
with Pythagoras and his school and with Aristarchus. "But" (as Dreyer
says in his most interesting book, _Tycho Brahe_) "proofs of the
physical truth of his system Copernicus had given none, and could give
none," any more than Pythagoras or Aristarchus.

There was nothing so startlingly simple in his system as to lead the
cautious astronomer to accept it, as there was in the later Keplerian
system; and the absence of parallax in the stars seemed to condemn his
system, which had no physical basis to recommend it, and no
simplification at all over the Egypto-Tychonic system, to which
Copernicus himself drew attention. It has been necessary to devote
perhaps undue space to the interesting work of Copernicus, because by
a curious chance his name has become so widely known. He has been
spoken of very generally as the founder of the solar system that is
now accepted. This seems unfair, and on reading over what has been
written about him at different times it will be noticed that the
astronomers--those who have evidently read his great book--are very
cautious in the words with which they eulogise him, and refrain from
attributing to him the foundation of our solar system, which is
entirely due to Kepler. It is only the more popular writers who give
the idea that a revolution had been effected when Pythagoras' system