Weather signs and the refutation of astrology

In the same way, when the moon is surrounded by a halo, and when the so-called halos form around the sun, they indicate either an abundance of moisture in the air or the onset of violent winds. And when what they call counter-suns accompany the sun's course, these too become signs of certain disturbances in the air. So also the rods that appear upright in the clouds with the color of a rainbow point to rain or extraordinary storms, or in general indicate above all a change in the atmosphere. Those who have devoted themselves to these matters have also observed many signs connected with the moon's waxing and waning, since the air around the earth necessarily changes along with the moon's phases. For when the moon is thin and clear on about the third day, it promises settled fair weather; but when it appears thick, with reddish horns, it threatens either violent rain from the clouds or a forceful south wind. Who does not know how much benefit these signs bring to daily life? A sailor can keep his vessel inside the harbor when he foresees the dangers from the winds. A traveler can avoid harm from afar by waiting out the change signaled by the gloominess of the air. And farmers, who labor over seeds and the care of plants, find from these signs all the right times for their work. The Lord has also foretold that signs of the dissolution of the universe will appear in the sun and the moon and the stars: "The sun will be turned to blood, and the moon will not give its light" (Joel 2:31; cf. Acts 2:20). These are signs of the completion of all things.

But those who leap beyond the bounds drag the discussion to the defense of astrology, and they say that our life is bound to the movement of the heavenly bodies, and that this is why the Chaldeans derive from the stars their predictions of what happens to us. They take the simple statement of Scripture, "Let them be for signs," and twist it to their own liking, as if it referred not to changes in the air or the seasons but to the allotment of human lives. For what do they say? They say that the interweaving of certain moving stars with the stars positioned in the zodiac, when they come together in a particular configuration, produces certain births; and that a different relation of these same stars produces the opposite allotment of life. About these matters it is perhaps not useless, for the sake of clarity, to go back a little and speak. I will say nothing of my own invention, but I will use their own arguments against them for their refutation—offering a kind of healing to those already caught in the harm, and security to the rest so that they do not fall into the same errors. The inventors of this astrology, having observed that in the broad span of time many of the configurations escaped them, confined the measures of time to an extremely narrow point. They claim that even the very smallest and most instantaneous moment—what the apostle calls "in an atom, in the twinkling of an eye" (1 Corinthians 15:52)—makes the greatest difference between one birth and another. The one born in this instant, they say, will be a tyrant over cities and a ruler of peoples, exceedingly wealthy and powerful; while the one born in the other moment of time will be a beggar and a vagabond, going from door to door for his daily food.