WHAT, then, causes the breakdowns of civilizations? Before applying our own method, which involves the marshalling of the relevant concrete facts of history, we had better pass in review certain solutions of the problem which soar higher in search of their evidence and rely for proof either on unprovable dogmas or else on things outside the sphere of human history.
One of the perennial infirmities of human beings is to ascribe their own failure to forces that are entirely beyond their control. This mental manoeuvre is particularly attractive to sensitive minds in periods of decline and fall; and in the decline and fall of the Hellenic Civilization it was a commonplace of various schools of philosophers to explain the social decay which they deplored but could not arrest as the incidental and inevitable effect of an allpervasive onset of 'cosmic senescence'. This was the philosophy of Lucretius (cf. De Rerum Natura, Bk. II, ll. 1144-74) in the last generation of the Hellenic time of troubles, and the same theme recurs in a work of controversy written by one of the Fathers of the Western Church, St. Cyprian, when the Hellenic universal state was beginning to break up three hundred years later. He writes:
'You ought to be aware that the age is now senile. It has not now the stamina that used to make it upstanding, nor the vigour and robustness that used to make it strong.... There is a diminution in the winter rains that give nourishment to the seeds in the earth, and in the summer heats that ripen the harvests.... This is the sentence that has been passed upon the World; this is the law of God; that what has been must die, and what has grown up must grow old.'
Modern physical science has knocked the bottom out of this theory, at any rate so far as any civilization now extant is concerned. It is true that modern physicists envisage, in an unimaginably distant future, a 'running down' of the 'clock' of the Universe as a consequence of the inevitable transformation of matter into radiation, but that future is, as we have said, unimaginably distant. Sir James Jeans writes:
'Taking a very gloomy view of the future of the human race, let us suppose that it can only expect to survive for two thousand million years longer, a period about equal to the past age of the Earth. Then, regarded as a being destined to live for three-score years and ten, Humanity, although it has been born in a house only seventy years old, is itself only three days old.... Utterly inexperienced beings, we are standing at the first flush of the dawn of civilization.... In time the glory of the morning must fade into the light of common day, and this,