Book 2, Chapter 42

87 “For what magistrate or man of any distinction consults lots? Elsewhere, indeed, lots have quite lost their following. Clitomachus writes that Carneades used to say he had never seen Fortune more fortunate than at Praeneste. Let us dismiss this kind of divination, then.

“Let us come to the Chaldeans’ monstrous claims. Eudoxus, a pupil of Plato and, in the judgment of the most learned men, easily foremost in astronomy, held—and left his opinion in writing—that the Chaldeans deserve no belief whatever when they predict and chart a person’s life from his birthday.

88 “Panaetius, the only Stoic to reject the astrologers’ predictions, also names Anchialus and Cassander, the greatest astronomers of his own time: distinguished though they were in the other branches of astronomy, they did not practice this kind of prediction. Scylax of Halicarnassus, a friend of Panaetius, eminent in astronomy and a leading statesman in his own city, rejected this entire Chaldean method of prediction.

89 “But let us set witnesses aside and use reason. Those who defend these Chaldean predictions from birthdays argue as follows. There is, they say, a certain power in the belt of constellations called ζωδιακός in Greek, the ‘zodiac,’ such that each part of this belt acts upon and changes the atmosphere in a different way, according to the stars occupying that part and the neighboring regions at any given time. This power is variously affected by the heavenly bodies called ‘wanderers.’ When these enter the very part of the belt that was rising at someone’s birth, or a part related or in harmony with it, they speak of ‘trines’ and ‘squares.’ Since the advance and retreat of heavenly bodies bring such great revolutions and changes in the sky with the seasons of the year and their weather, and since we see what effects the sun’s power produces, they consider it not merely plausible but true that newborn children receive life and take shape according to the state of the air. From this, they say, come each person’s talents, character, mind, body, course of life, chances, and outcomes.

87 “What magistrate, or what man of any distinction, uses lots? In other places lots have fallen completely out of use. According to Clitomachus, Carneades often remarked, ‘Nowhere have I seen Fortune enjoy better fortune than at Praeneste.’ So let us leave this kind of divination aside.

“Let us turn to the monstrous claims of the Chaldeans. Eudoxus, a student of Plato and easily the leading astronomer in the judgment of the most learned men, left his view of them in writing. He thought we should put no trust at all in the Chaldeans when they predict and describe someone's life from his date of birth.

88 “Panaetius was the only Stoic to reject astrologers' predictions. He also names Anchialus and Cassander, the foremost astronomers of his own time. Despite their distinction in other areas of astronomy, they made no predictions of this sort. Panaetius' friend Scylax of Halicarnassus combined outstanding knowledge of astronomy with a leading role in governing his own city. He rejected this whole Chaldean method of prediction.

89 “Enough of witnesses; let us reason it through. Here is the argument made in defense of the Chaldeans' birth-based predictions. They say a certain force exists in the belt of constellations called the zodiac in Greek. Each part of this circle affects and changes the sky differently, depending on which stars are in that part and the neighboring parts at any given time. The stars called wandering stars affect this force in different ways. When they enter the very part of the circle where the newborn's rising sign lies, or a part connected or in harmony with it, they call those positions triangles and squares. The approach and retreat of the stars cause such great changes and shifts in the sky over the year and its seasons. And the sun's force produces the effects we see. For these reasons, they think it not just likely but true that children receive their life and form at birth according to the condition of the air. This, they say, shapes each person's abilities, habits, mind, body, way of life, accidents, and outcomes.