prudent astrologers always made a reservation as to public calamities which proceed from universal causes. Difference of education, mode of life, and similar circumstances explained the different fates which people born at the same time met with; and as to twins, they were not born exactly at the same moment, and one was always naturally weaker than the other, and this the stars could not correct. Astrology was not forbidden in the Bible, but sorcery only.
So far Tycho's astrological ideas are in accordance with those of contemporary and previous writers on such subjects, but towards the end of his discourse he shows more distinctly than most of these, that he did not consider the fate of man to be absolutely settled by the aspect of the stars, but that God could alter it as He willed. Nor was man altogether bound by the influence of the stars, but God had so made him that he might conquer that influence, as there was something in man superior to it. The objection to astrology, that it was a useless art, as knowledge of the future was undesirable, would only hold good if it were impossible to resist the influence of the stars; but being forewarned, we might try to avert the threatening evils, and in this way astrology was of great use.
In conclusion, Tycho stated that as the doctrine of the primum mobile (spherical astronomy) was very easy, and was frequently lectured on in the University, he had thought it more advisable to take for his subject the motions of secundum mobile, explain the method of calculating the motions of the seven planets by the Prutenic tables, which were the most accurate ones, and describe the circles by means of which the tables had been computed.
Early in 1575 these lectures were finished, and Tycho Brahe shortly afterwards started on the long-deferred
