The idea of the universe which prevailed throughout the Middle Ages, and the general orientation of men’s thoughts were incompatible with some of the fundamental assumptions which are required by the idea of Progress. According to the Christian theory which was worked out by the Fathers, and especially by St. Augustine, the whole movement of history has the purpose of securing the happiness of a small portion of the human race in another world; it does not postulate a further development of human history on earth. For Augustine, as for any medieval believer, the course of history would be satisfactorily complete if the world came to an end in his own lifetime. He was not interested in the question whether any gradual amelioration of society or increase of knowledge would mark the period of time which might still remain to run before the day of Judgment. In Augustine’s system the Christian era introduced the last period of history, the old age of humanity, which would endure only so long as to enable the Deity to gather in the predestined number of saved people. This theory might be combined with the widely-spread belief in a millennium on earth, but the conception of such a dispensation does not render it a theory of Progress.
Again, the medieval doctrine apprehends history not as a natural development but as a series of events ordered by divine intervention and revelations. If humanity had been left to go its own way it would have drifted to a highly undesirable port, and all men would have incurred the fate of everlasting misery from which supernatural interference rescued the minority. A belief in Providence might indeed, and in a future age would, be held along with a belief in Progress, in the same mind; but the fundamental assumptions were incongruous, and so long as the doctrine of Providence was undisputedly in the ascendant, a doctrine of Progress could not arise. And the doctrine of Providence, as it was developed in Augustine’s “City of God,” controlled the thought of the Middle Ages.
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).]