The best excuse ever made for astrology was that offered by the great astronomer, Kepler, himself an unwilling practiser of the art.
He had many applications from his friends to cast nativities for them, and generally gave a positive refusal to such as he was not afraid of offending by his frankness. In other cases he accommodated himself to the prevailing delusion. In sending a copy of his Ephemerides to Professor Gerlach, he wrote, that they were nothing but worthless conjectures; but he was obliged to devote himself to them, or he would have starved. “Ye overwise philosophers,” he exclaimed, in his Tertius Interveniens; “ye censure this daughter of astronomy beyond her deserts! Know ye not that she must support her mother by her charms? The scanty reward of an astronomer would not provide him with bread, if men did not entertain hopes of reading the future in the heavens.”
Necromancy was, next to astrology, the pretended science most resorted to, by those who wished to pry into the future. The earliest instance upon record is that of the witch of Endor and the spirit of Samuel. Nearly all the nations of antiquity believed in the possibility of summoning departed ghosts to disclose the awful secrets that God made clear to the disembodied. Many passages in allusion to this subject will at once suggest themselves to the classical reader; but this art was never carried on openly in any country. All governments looked upon it as a crime of the deepest dye. While astrology was encouraged, and its professors courted and rewarded, necromancers were universally condemned to the stake or the gallows. Roger Bacon, Albertus Magnus, Arnold of Villeneuve, and many others, were accused by the public opinion of many centuries, of meddling in these unhallowed matters. So deep-rooted has always been the popular delusion with respect to accusations of this kind, that no crime was ever disproved with such toil and difficulty. That it met great encouragement, nevertheless, is evident from the vast numbers of pretenders to it; who, in spite of the danger, have existed in all ages and countries.