Astrology might rest on a better foundation than magic. For if no one has seen farfadets, or lemures, or dives, or peris, or demons, or cacodemons, the predictions of astrologers have often been found true. Let two astrologers be consulted on the life of an infant, and on the weather; if one of them say that the child shall live to the age of man, the other that he shall not; if one foretell rain and the other fair weather, it is quite clear that there will be a prophet.

The great misfortune of astrologers is that the heavens have changed since the rules of the art were laid down. The sun, which at the equinox was in the Ram in the time of the Argonauts, is now in the Bull; and astrologers, most unfortunately for their art, now attribute to one house of the sun that which visibly belongs to another. Still, this is not a demonstrative argument against astrology. The masters of the art are mistaken; but it is not proved that the art cannot exist.

There would be no absurdity in saying, “Such a child was born during the moon’s increase, in a stormy season, at the rising of a certain star; its constitution was bad, and its life short and miserable, which is the ordinary lot of weak temperaments; another, on the contrary, was born when the moon was at the full, and the sun in all his power, in calm weather, at the rising of another particular star; his constitution was good, and his life long and happy.” If such observations had been frequently repeated, and found just, experience might, at the end of a few thousand centuries, have formed an art which it would have been difficult to call in question; it would have been thought, not without some appearance of truth, that men are like trees and vegetables, which must be planted only in certain seasons. It would have been of no service against the astrologers to say, “My son was born in fine weather, yet he died in his cradle.” The astrologer would have answered, “It often happens that trees planted in the proper season perish prematurely; I will answer for the stars, but not for the particular conformation which you communicated to your child; astrology operates only when there is no cause opposed to the good which they have power to work.”

Nor would astrology have suffered any more discredit from it being said: “O............