The Refutation of All Heresies: Book IV. 5Another Method of Fixing the Horoscope at Birth; Equally Futile; Use of the Clepsydra in Astrology; The Predictions of the Chaldeans Not Verified.

In this way, the art practised by the Chaldeans will be shown to be unstable. Should any one, however, allege that, by questions put to him who inquires from the Chaldeans, the birth can be ascertained, not even by this plan is it possible to arrive at the precise period. For if, supposing any such attention on their part in reference to their art to be on record, even these do not attain--as we have proved--unto accuracy either, how, we ask, can an unsophisticated individual comprehend precisely the time of parturition, in order that the Chaldean acquiring the requisite information from this person may set the horoscope correctly? But neither from the appearance of the horizon will the rising star seem the same everywhere; but in one place its declination will be supposed to be the horoscope, and in another the ascension (will be thought) the horoscope, according as the places come into view, being either lower or higher. Wherefore, also, from this quarter an accurate prediction will not appear, since many may be born throughout the entire world at the same hour, each from a different direction observing the stars.

But the supposed comprehension (of the period of parturition) by means of clepsydras is likewise futile. For the contents of the jar will not flow out in the same time when it is full as when it is half empty; yet, according to their own account, the pole itself by a single impulse is whirled along at an equable velocity. If, however, evading the argument, they should affirm that they do not take the time precisely, but as it happens in any particular latitude, they will be refuted almost by the sidereal influences themselves. For those who have been born at the same time do not spend the same life, but some, for example, have been made kings, and others have grown old in fetters. There has been born none equal, at all events, to Alexander the Macedonian, though many were brought forth along with him throughout the earth; (and) none equal to the philosopher Plato. Wherefore the Chaldean, examining the time of the birth in any particular latitude, will not be able to say accurately, whether a person born at this time will be prosperous. Many, I take it, born at this time, have been unfortunate, so that the similarity according to dispositions is futile.

Having, then, by different reasons and various methods, refuted the ineffectual mode of examination adopted by the Chaldeans, neither shall we omit this, namely, to show that their predictions will eventuate in inexplicable difficulties. For if, as the mathematicians assert, it is necessary that one born under the barb of Sagittarius' arrow should meet with a violent death, how was it that so many myriads of the Barbarians that fought with the Greeks at Marathon or Salamis were simultaneously slaughtered? For unquestionably there was not the same horoscope in the case, at all events, of them all. And again, it is said that one born under the urn of Aquarius will suffer shipwreck: (yet) how is it that so many of the Greeks that returned from Troy were overwhelmed in the deep around the indented shores of Euboea? For it is incredible that all, distant from one another by a long interval of duration, should have been born under the urn of Aquarius. For it is not reasonable to say, that frequently, for one whose fate it was to be destroyed in the sea, all who were with him in the same vessel should perish. For why should the doom of this man subdue the (destinies) of all? Nay, but why, on account of one for whom it was allotted to die on land, should not all be preserved?