century in which Dante lived, there had been no progress in scientific knowledge. He still held to the four elements of the Greeks:
Thou sayest, the air, the fire I see,
The earth and water, and all things of them
Compounded, to corruption turn and soon
Dissolve.
Although Shakespeare was not born until twenty years after the death of Copernicus, all allusions made by him to the heavens are either astrological or Ptolemaic.
The tendency of a superstition to persist even after closely allied phenomena have been explained on a purely natural basis, is illustrated in the belief that planetary motion was due to "blessed movers." Although Copernicus discovered that the planets revolve around the sun instead of the earth, he still believed that their motion was controlled by guiding spirits. Galileo conclusively confirmed the correctness of the heliocentric theory, but faith in the supernatural motion of the planets was undisturbed. Not until the genius of Newton had discovered and formulated the law of universal gravitation and provided a mathematical foundation for Kepler's laws, were these conducting spirits dismissed. It required the discoveries of three men of genius and two centuries of time to overthrow the foolish superstition of mediocre man.
From the end of the fourth to the beginning of the fifteenth century superstition had given to society a form that prevented the man of genius from being heard. Buckle says that from the sixth to the tenth century there were not in all Europe more than three men who dared to think for themselves, and through fear of punishment even they were obliged to veil their meaning in mystical language. The remaining part of society was sunk in degrading ignorance. Progress became possible only when science essayed to explain observed phenomena by depending on natural causation.
For ages the superstitions of astrology ruled the world by the terror that they inspired. The figure of a man, with entrails exposed, in the front of the family almanac is a survival of Egyptian astrology. Around the figure are the twelve signs of the zodiac with lines extending to the parts of the body supposed to be influenced by the celestial signs. Aries the head, Leo the heart, Capricornus the knees, Pisces the feet, etc. Faith in the influence of the signs of the zodiac remained unshaken in spite of knowledge that the inconstant stars were shifting from one sign to another by the precession of the equinoxes. When the pyramids were built, what is now known as the pole star was so far from the celestial pole that the Egyptians saw it rise and set in the Mediterranean. The Southern Cross was then visible not only in northern Egypt but throughout Europe as far north as London.
Coincidences have ever been mistaken for causes. Owing to the
