Illustrative of the attitude of the Stoics towards positive religion are their views on divination. [990] The importance attached by them to the prophetic art appears in the diligence which the chiefs of this School devoted to discussing it. The ground for the later teaching having been prepared by Zeno and Cleanthes, Chrysippus gave the finishing touch to the Stoic dogmas on the subject. [991] Particular treatises respecting divination were drawn up by Sphærus, Diogenes, Antipater, and, last of all, by Posidonius. [992] The subject was also fully treated by Boëthus, and by Panætius from a somewhat different side. [993] The common notions as to prognostics and oracles could not commend themselves to these philosophers, nor could they approve of common soothsaying. In a system so purely based on nature as theirs, [994] the supposition that God works for definite ends after the manner of men, exceptionally announcing to one or the other a definite result—in short, the marvellous—was out of place. But to infer thence—as their opponents, the Epicureans, did—that the whole art of divination is a delusion, was more than the Stoics could do. The belief in an extraordinary care of God for individual men was too comforting an idea for them to renounce; [995] they not only appealed to divination as the strongest proof of the existence of Gods and the government of Providence, [996] but they also drew the converse conclusion, that, if there be Gods, there must also be divination, since the benevolence of the Gods would not allow them to refuse to mankind so inestimable a gift. [997] The conception of destiny, too, and the nature of man, appeared to Posidonius to lead to the belief in divination; [998] if all that happens is the outcome of an unbroken chain of cause and effect, there must be signs indicating the existence of causes, from which certain effects result; [999] and if the soul of man is in its nature divine, it must also possess the capacity, under circumstances, of observing what generally escapes its notice. [1000] Lest, however, the certainty of their belief should suffer from lacking the support of experience, the Stoics had collected a number of instances of verified prophecies; [1001] but with so little discrimination, that we should only wonder at their credulity, did we not know the low state of historical criticism in their time, and the readiness with which, in all ages, men believe whatever agrees with their prejudices. [1002]