Inasmuch as to this ruler, who was a man of culture and an inquirer into all branches of learning, malicious persons have attributed the use of evil arts to learn the future, we shall briefly indicate how a wise man is able to acquire this by no means trivial variety of knowledge. The spirit behind all the elements, seeing that it is incessantly and everywhere active in the prophetic movement of everlasting bodies, bestows upon us the gift of divination by those methods which we acquire through divers studies; and the forces of nature, propitiated by various rites, as from exhaustless springs provide mankind with prophetic utterances.[223] That is, we can foreknow, if not control, the results of the processes of universal nature. Since it is through the forces of nature that we do this, augury, oracular utterances, oneiromancy and astrology all become for Ammianus but subdivisions of physical science. He admits that there are persons who disagree with him, who object that predictions are often erroneous; but against such persons he employs the old refutation that occasional mistakes are to be attributed to man’s imperfect knowledge and faulty observation, and that by such mistakes the validity of divination is no more disproved than is grammar forever discredited because a grammarian speaks incorrectly, or music because a musician sings out of tune.[224] Opposition to the arts of divination he calls “vanities plebeia,” and upon such loud-mouthed ignorance of the vulgar he looks down with much the same superior smile that the lover of speculative philosophy to-day bestows upon the man in the street who irritably disputes the utility of that subject. Indeed, the strength of Ammianus’s attachment to divination is so great that he quotes its arch-opponent, Cicero, in its support. For he concludes his discussion of the subject in these words: “Wherefore in this as in other matters Tully says most admirably, ‘Signs of future events are shown by the gods.’”[225] Unless perchance Ammianus was acquainted with the first book only of _De Divinatione_, this remark—which ought to have proved more potent than any necromantic spell in invoking Cicero’s slandered Manes—must be taken as a startling revelation of the mental calibre of both its maker and his age.