Against the Chaldean Art

In each sign of the zodiac they mark off what they call the bounds of the stars: the stretches within which each star, running from one degree to another, can exert the most influence. On these there is no small disagreement among them, as their own tables show. [a]

They say that stars have a bodyguard when they stand in the middle of other stars along a run of consecutive signs. Suppose one star occupies the first degrees of a sign, another the last, and another the degrees in between: the one in the middle is said to be guarded by the two holding the degrees at either end. And stars are said to look at one another, and to agree with one another, when they appear at the points of a triangle or a square. Those with a gap of three signs between them form a triangle and look at one another; those with a gap of two form a square. And as the lower parts of the body feel with the head, and the head with the parts below it, so earthly things feel with the things above the moon. But there is also a certain difference among them, a failure to feel together, so that they do not hold one and the same point of union.

Euphrates the Peratic and Acembes the Carystian and the rest of that chorus made use of all this. They gave things names foreign to the account of the truth, and speak of a faction among the Ages, and a defection of good powers over to evil ones, and an agreement of good with wicked, calling them Toparchs and Suburbans and a great many other names besides. I will set out the whole of that heresy, as they have attempted it, and refute it when I come to the account of these things. [d]

But for now, so that no one supposes what the Chaldeans hold about astrological learning to be reliable and secure, I will not hesitate to set down a short refutation of them. The art is futile. It is better at leading a soul astray and wiping it out, while it hopes for empty things, than at helping it. And we take our stand against these men not from any experience of the art itself, but from a knowledge of how arguments work in practice. The men who took up this learning became pupils of the Chaldeans, passed their mysteries on to people as something foreign and marvelous, changed the names, and put together their heresy out of that. But since they think the astrologers’ art a powerful one, and use the testimony its own defenders supply, and want their own attempts believed on that footing, we will now, as seems best, show that astrology will not stand — since we intend after this to overturn the Peratic system as well, a branch grown out of an unstable root.

The starting point of the whole art, and its foundation, so to speak, is setting the horoscope. From this the rest of the angles are taken, and the houses that fall away from them and the houses that follow them, and the triangles and the squares and the arrangements of the stars that go with them; and from all of these come the predictions. So if the horoscope is taken away, it follows necessarily that neither the midheaven nor the setting point nor the point opposite the midheaven can be identified; and if these cannot be grasped, the whole Chaldean method disappears along with them. [g]

That the sign on the horoscope cannot be found by them may be shown in a number of ways. For it to be grasped, three things are needed. First, the birth of the person under examination has to be firmly fixed. Second, the instrument that marks it has to be unerring. Third, the rising of the zodiacal sign has to be observed exactly. At the moment of delivery the rising of the sign coming up in the sky must be watched, since the Chaldeans, once they have determined the sign on the horoscope, draw up the configuration of the stars to match that rising — they call it the chart — and lay their predictions on it. But it is not possible to take the birth of the people under examination, as I will show; nor is the instrument unerring; nor is the rising sign grasped exactly.

Let me say now how the Chaldeans’ method will not stand. Having first marked the matter out for investigation, they take the birth of the person under examination either from the depositing of the seed and conception, or from the delivery. If someone tries to take it from conception, an exact account of that is out of reach, since the time involved is quick — and naturally so. We cannot say whether conception happens at the moment the seed is transferred or not. It can happen as fast as a thought, the way fat touched to a red-hot oven sets at once. But it can also happen after an interval. Since there is a distance from the mouth of the womb to its far end, where physicians say conceptions take place, the seed once deposited naturally takes some time to cross that distance. The Chaldeans, then, not knowing the exact amount of that time, will never grasp the conception. At one time the seed is shot straight and falls all at once on the parts of the womb well suited to conceiving; at another it drops scattered, and is gathered into one place by the womb’s own power. And while these things are unknown — when the first happens and when the second, how much time is spent on this conception and how much on that — while ignorance on these points holds, an exact grasp of conception is out of the question.

And if, as some of the natural philosophers have said, the seed is first cooked and altered in the womb and only then enters the vessels that have opened to it, as the seeds of the earth sink into the ground, then it follows that men who do not know how long that change takes will not know the moment of conception either. Besides, as women differ from one another in the other parts of the body, in their working and in everything else, it is reasonable that they differ in the working of the womb as well, some conceiving faster and some slower. That is no wonder, since even the same women, compared with themselves, are at times seen to conceive readily and at other times not at all. And when this is so, it is impossible to say exactly when the deposited seed takes hold, so that the Chaldeans might set the horoscope of the birth from that moment.

For this reason the horoscope cannot be set from conception. But neither can it be set from delivery. In the first place, there is the difficulty of saying when a delivery has happened: when the child begins to come out into the cold air, or when it protrudes a little, or when it is set down on the ground. In none of these cases is it possible to grasp the exact moment of delivery or to fix the time. Because of the resolve of the soul, and the fitness of the body, and the choice of place, and the midwife’s skill, and countless other causes, the time is not the same at which the child comes forward once the membranes have burst, or comes a little way out, or is laid on the ground: it differs from one case to another. And since the Chaldeans cannot measure this definitely and exactly, they will fail, as they must, to fix the hour of the birth. [j]

That the Chaldeans claim to know the horoscope at the moment of delivery, but in fact do not know it, is clear from all this. That their instrument is not unerring either is easy to work out. They say that the person sitting beside the woman in labor signals to the Chaldean by striking a metal disc, and that the Chaldean, watching the stars from a hilltop, looks up and marks down the rising sign. First, we will show them that when the delivery itself is indefinite, as we proved a little earlier, it is not even easy to signal it by striking the disc. But grant that the delivery can be grasped: it still cannot be signaled at the exact time. The noise of the disc can be divided over a long stretch of time as it travels to the ear, and so the sound reaches the height late. Watch men felling timber at a distance and you have the proof: a good while after the axe has come down, the sound of the blow is heard, taking that much longer to arrive.

For this reason too, then, the Chaldeans cannot take the exact time of the rising sign, and so cannot take the time at which the horoscope could truly be set. And it is not only that more time passes after the delivery — the man sitting beside the woman in labor strikes the disc, and then the sound reaches the man who has gone up to the height. While he is glancing around and looking to see which sign the moon is in, and which each of the other stars is in, the arrangement of the stars necessarily becomes a different one, since the motion of the pole carries them along at a speed beyond describing, before what is seen in the sky can be carefully matched to the moment the child was born.

In this way the art the Chaldeans practice will be shown not to stand. Suppose someone claims that the birth can be worked out from the questions the inquirer is asked — his own birth, or the birth of the person he is asking about. Not even that way can the exact time be reached. If so much care over their art is on record among them, and even they do not reach exactness, as we have shown, how has an ordinary man grasped the time of a delivery precisely, so that the Chaldean, learning it from him, could set the horoscope truly? Nor will the same star even seem to be rising everywhere, given how the horizon looks from one place and another: here the house that falls away will be taken for the horoscope, and there the house that follows, depending on whether the ground lies lower or higher. So on this count too the prediction will not turn out exact, since many are born at the same hour all over the world, each of them seeing the stars from a different angle. [l]

The supposed grasp of the time by water clocks is futile as well. The jar will not run out at the same rate when it is full as when it is nearly empty — while the pole itself, by their own account, is carried around at an even speed by a single impulse. And if they wriggle out of the argument and say that they do not take the time precisely but roughly, within a margin, they will be all but refuted by the outcomes themselves. Men born at the same time have not lived the same life. Some, for instance, have reigned as kings, and others have grown old in chains. No one at all turned out equal to Alexander the Macedonian, though many were born along with him throughout the inhabited world; no one equal to Plato the philosopher. So the Chaldean, taking the time of a birth only within a margin, will not be able to say with any accuracy whether a man born at that time will prosper. Plenty born at that same time have been unfortunate — so the likeness the charts are supposed to give is worthless.

Having refuted the Chaldeans’ laborious and useless inquiry in different ways and by several methods, we will not leave this out either: that their predictions run into difficulties they cannot get out of. If a man born under the barb of Sagittarius’ arrow must, as the mathematicians say, be cut down, how were so many tens of thousands of the barbarians who fought the Greeks at Marathon or Salamis slaughtered all at once? Surely they did not all have the same horoscope. And again, they say that a man born under the urn of Aquarius will suffer shipwreck. How then were so many of the Greeks sailing home from Troy drowned together around the Hollows of Euboea? It is not credible that all of them, separated from one another by long stretches of time, were born under the urn of Aquarius. Nor is it reasonable to say that, again and again, on account of one man whose fate it was to be destroyed at sea, everyone in the same ship perishes with him. Why should this one man’s fate defeat the fates of all the rest? And why should not everyone be saved on account of the one whose fate it was to die on land?

They also give an account of the working of the zodiacal signs, saying that children born under them are made to resemble them, and we will not leave that out either. A man born in Leo, they say, will be brave; a man born in Virgo will have straight hair, a fair complexion, no children, and a modest manner. These claims, and others like them, deserve laughter rather than serious attention. By their account no Ethiopian can be born in Virgo — and if one is, they will have to grant that he is white, straight-haired, and the rest of it. I think rather that the ancients attached the names of familiar animals to certain groups of stars in order to know them better, not because of any likeness in nature. What do seven stars, standing far apart from one another, have in common with a bear? Or five with the head of a dragon — the five of which Aratus says: [p]

In this way these things too are shown not to be worth so much labor, to anyone who prefers to think straight and does not attend to the Chaldeans’ inflated talk. They wipe kings out by fitting them with cowardice, and they stir private men up to dare great things. And if a man, impaled on some evil, comes to grief, the one who has been harmed does not become a teacher to all the rest — whom the astrologers still mean to fool. When their forecasts fail, they push those men’s minds off into the endless, saying that the same stars cannot come back into the same configuration except by the return of the Great Year, at the end of seven thousand seven hundred and seventy-seven years. How, then, will human observation manage to keep pace with so many ages for the sake of a single birth — and this not once, but many times over? The Chaldaic art needed refuting at greater length than one would expect, though we brought it up on account of other matters and not for its own sake. [q]

But since we have decided to leave out none of the opinions put forward among the nations, on account of the many-voiced cunning of the heresies, let us see what is said as well by the men who have made bold to lay down teachings about magnitudes. Seeing the wasted labor of most of the rest, each of whom lied in his own way and gained a name by it, they ventured on something bigger, so that men who greatly admired the small lies might admire them the more. They assume circles and measures, triangles and squares, in twofold and threefold array. There is a great deal to say on this, but it is not necessary for the matter we have in hand.