Therefore, while the replacement of the mundane civilizations by the world-wide and enduring reign of the Church Militant on Earth would certainly produce what to-day would seem a miraculous improvement in those mundane social conditions which the civilizations have been seeking to improve during the last six thousand years, the aim, and test, of progress under a truly Christian dispensation on Earth would not lie in the field of mundane social life; the field would be the spiritual life of individual souls in their passages through this earthly life from birth into this world to death out of it.
But if spiritual progress in time in this world means progress achieved by individual human souls during their passages through this world to the other world, in what sense can there be any spiritual progress over a time-span far longer than that of individual lives on Earth, and running into thousands of years, such as that of the historical development of the higher religions from the rise of Tammuz-worship and the generation of Abraham to the Christian era?
I have already confessed my own adherence to the traditional Christian view that there is no reason to expect any change in unredeemed human nature while human life on Earth goes on. Till this Earth ceases to be physically habitable by man, we may expect that the endowments of individual human beings with original sin and with natural goodness will be about the same, on the average, as they always have been as far as our knowledge goes. the most primitive societies known to us in the life or by report provide examples of as great natural goodness as, and no lesser wickedness than, the highest civilizations or religious societies that have yet come into existence. There has been no perceptible variation in the average sample of human nature in the past; there is no ground, in the evidence afforded by History, to expect any great variation in the future either for better or for worse.
The matter in which there might be spiritual progress in time on a time-span extending over many successive generations of life on Earth is not the unregenerate nature of man, but the opportunity open to souls, by way of the learning that comes through suffering, for getting into closer communion with God, and becoming less unlike Him, during their passage through this world.
What Christ, with the Prophets before Him and the Saints after Him, has bequeathed to the Church, and what the Church, by virtue of having been fashioned into an incomparably effective institution, succeeds in accumulating, preserving, and communicating to successive generations of Christians, is a growing fund of illumination and of grace-meaning by ‘illumination’ the discovery of revelation or revealed discovery of the true nature of God and the true end of man here and hereafter, and by ‘grace,’ the will or inspiration or inspired will to aim at getting into Him. In this matter of increasing spiritual opportunity for souls in their passages through life on Earth, there is assuredly an inexhaustible possibility of progress in this world.