The stories of miracles, then, are to be rejected on _a priori_ rational grounds, but in the case of events which we know to have happened the scientific historian will not rest till he has discovered their natural causes which, for instance, in the case of the wonderful rise of the Roman Empire—the most marvellous thing, Polybius says, which God ever brought about {72a}—are to be found in the excellence of their constitution (_τῇ ἰδιότητι τῆς πολιτείας_), the wisdom of their advisers, their splendid military arrangements, and their superstition (_τῇ δεισιδαιμονίᾳ_). For while Polybius regarded the revealed religion as, of course, objective reality of truth, {72b} he laid great stress on its moral subjective influence, going, in one passage on the subject, even so far as almost to excuse the introduction of the supernatural in very small quantities into history on account of the extremely good effect it would have on pious people. But perhaps there is no passage in the whole of ancient and modern history which breathes such a manly and splendid spirit of rationalism as one preserved to us in the Vatican—strange resting-place for it!—in which he treats of the terrible decay of population which had fallen on his native land in his own day, and which by the general orthodox public was regarded as a special judgment of God sending childlessness on women as a punishment for the sins of the people. For it was a disaster quite without parallel in the history of the land, and entirely unforeseen by any of its political-economy writers who, on the contrary, were always anticipating that danger would arise from an excess of population overrunning its means of subsistence, and becoming unmanageable through its size. Polybius, however, will have nothing to do with either priest or worker of miracles in this matter. He will not even seek that ‘sacred Heart of Greece,’ Delphi, Apollo’s shrine, whose inspiration even Thucydides admitted and before whose wisdom Socrates bowed. How foolish, he says, were the man who on this matter would pray to God. We must search for the rational causes, and the causes are seen to be clear, and the method of prevention also. He then proceeds to notice how all this arose from the general reluctance to marriage and to bearing the expense of educating a large family which resulted from the carelessness and avarice of the men of his day, and he explains on entirely rational principles the whole of this apparently supernatural judgment.