Favorinus denied that the doctrine of nativities was the work of the Chaldeans and regarded it as the more recent invention of marvel-mongers, tricksters, and mountebanks. He regards the inference from the effect of the moon on tides to that of the stars on every incident of our daily life as unwarranted. He further objects that if the Chaldeans did record astronomical observations these would apply only to their own region and that observations extended over a vast lapse of time would be necessary to establish any system of astrology, since it requires ages before the stars return to their previous positions. Like Cicero, Favorinus probably manifests his ignorance of the technique of astrology in complaining that astrologers do not allow for the different influence of different constellations in different parts of the earth. More cogent is his suggestion that there may be other stars equal in power to the planets which men cannot see either for their excess of splendor or because of their position. He also objects that the position of the stars is not the same at the time of conception and the time of birth, and that, if the different fate of twins may be explained by the fact that after all they are not born at precisely the same moment, the time of birth and the position of the stars must be measured with an exactness practically impossible. He also contends that it is not for human beings to predict the future and that the subjection of man not merely in matters of external fortune but in his own acts of will to the stars is not to be borne. These two arguments of the divine prerogative and of human free will became Christian favorites. He complains that the astrologers predict great events like battles but cannot predict small ones, and declares that they may congratulate themselves that he does not propose such a question to them as that of astral influence on minute animals. This and his further question why, out of all the grand works of nature, the astrologers limit their attention to petty human fortune, suggest that like Cicero he did not realize that astrology was or would become a theory of all nature and not mere genethlialogy. [Sidenote: Sextus Empiricus.]