But that is not all; for we have seen that any kind of magical force is only infallible as a tendency; it may be counteracted, and this is generally thought to be the case with Omens. Just as the rites of one magician may be frustrated by the more powerful operations of another, so an Omen indicates a course of events which may, perhaps, be turned aside. That which is foreseen by one spirit may be prevented by another, whose intervention was not foreseen; for spirits are by no means infallible. Hence, however well observed and interpreted, the tendency of an Omen, or of the force it manifests, may be diverted or reversed by some unknown cause. Moreover, we ourselves are loth to relinquish all control over affairs. We have seen that the efficacy of Omens depended (not without reason) on the way they were received; and that we may meet them with our own magical influence, accepting them, or rejecting with a spell. And further, we have seen that Magic often works by symbols, and that a symbolic action will cause or incite a real event; and similarly it is believed that the event foreshown by an Omen may be symbolically fulfilled; that some harmless semblance of the event may be substituted for it, absorb (as it were) the poison of the menace and let the threatened man go free. Astyages dreamed a dream which the Magi interpreted to mean that the child of his daughter (married to a Persian) should reign over Asia in his stead—implying that the kingdom must pass from the Medes. He therefore took measures to have the child destroyed; but by a series of happy chances Cyrus, the child, escaped and grew up; and in his boyhood Astyages discovered who he was, and was greatly alarmed. So he sent again for the Magi; but they, on learning that the boys in the village where Cyrus had been reared had in games appointed him their king, decided that this fulfilled the dream; for, said they, “he will not reign a second time.”[378] So Cyrus lived, and the lordship of Asia passed to the Persians; for the Magi in this case overestimated the value of symbols. But all these ways of frustrating an Omen are incompatible with the interpretation of them by the course of Fate, and are only fit to be believed in by the weaker brethren. § 9. APOLOGY FOR OMENS