There was, moreover, the doctrine of original sin, an insuperable obstacle to the moral amelioration of the race by any gradual process of development. For since, so long as the human species endures on earth, every child will be born naturally evil and worthy of punishment, a moral advance of humanity to perfection is plainly impossible. [Footnote: It may be added that, as G. Monod observed, "les hommes du moyen age n'avaient pas conscience des modifications successives que le temps apporte avec lui dans les choses humaines" (Revue Historique, i. p. 8).] 2. But there are certain features in the medieval theory of which we must not ignore the significance. In the first place, while it maintained the belief in degeneration, endorsed by Hebrew mythology, it definitely abandoned the Greek theory of cycles. The history of the earth was recognised as a unique phenomenon in time; it would never occur again or anything resembling it. More important than all is the fact that Christian theology constructed a synthesis which for the first time attempted to give a definite meaning to the whole course of human events, a synthesis which represents the past as leading up to a definite and desirable goal in the future. Once this belief had been generally adopted and prevailed for centuries men might discard it along with the doctrine of Providence on which it rested, but they could not be content to return again to such views as satisfied the ancients, for whom human history, apprehended as a whole, was a tale of little meaning. [Footnote: It may be observed that Augustine (De Civ. Dei, x. 14) compares the teaching (recta eruditio) of the people of God, in the gradual process of history, to the education of an individual. Prudentius has a similar comparison for a different purpose (c. Symmachum, ii. 315 sqq.): Tardis semper processibus aucta Crescit vita hominis et longo proficit usu. Sic aevi mortalis habet se mobilis ordo, Sic variat natura vices, infantia repit, etc. Floras (Epitome, ad init.) had already divided Roman history into four periods corresponding to infancy, adolescence, manhood, and old age.] They must seek for some new synthesis to replace it.