Arnold Toynbee writes: The first three volumes of this work deal with the birth and growth of civilizations; the present three deal with their breakdown and disintegration. Why have some civilizations broken down in the past? I do not believe that civilizations are fated to break down, or that they have a fixed maximum life-span, as organisms have. On this point—and it is one of capital importance—I differ from that great man of genius, Oswald Spengler. I do not believe, either, that civilizations break down through being worsted by their environment. I believe that, when they do break down, the cause is, not some blow from outside, but some inward spiritual failure—some kind of demoralization to which we human beings are not bound to succumb and for which we ourselves therefore bear the responsibility. We can become demoralized by success. This may make us lazy or self-satisfied or conceited. We may be intoxicated with the pride that goes before a fall.