We start with the Liberal's Bible of History,'Tragedy and Hope
A History of The World in our Time' by Carroll Quigley.

.... There have always been men who have asked, "Where are we going?" But never, it would seem, have there been so many of them. And surely never before have these myriads of questioners asked their question in such dolorous tones or rephrased their question in such despairing words: "Can man survive?" Even on a less cosmic basis, questioners appear on all sides, seeking "meaning" or "identity," or even, on the most narrowly egocentric basis, "trying to find myself."

One of these persistent questions is typical of the twentieth century rather than of earlier times: Can our way of life survive? Is our civilization doomed to vanish, as did that of the Incas, the Sumerians, and the Romans? From Giovanni Battista Vico in the early eighteenth century to Oswald Spengler in the early twentieth century and Arnold J. Toynbee in our own day, men have been puzzling over the problem whether civilizations have a life cycle and follow a similar pattern of change. From this discussion has emerged a fairly general agreement that men live in separately organized societies, each with its own distinct culture; that some of these societies, having writing and city life, exist on a higher level of culture than the rest, and should be called by the different term "civilizations"; and that these civilizations tend to pass through a common pattern of experience.

From these studies it would seem that civilizations pass through a process of evolution which can be analyzed briefly as follows: each civilization is born in some inexplicable fashion and, after a slow start, enters a period of vigorous expansion, increasing its size and power, both internally and at the expense of its neighbors, until gradually a crisis of organization appears.

When this crisis has passed and the civilization has been reorganized, it seems somewhat different. Its vigor and morale have weakened. It becomes stabilized and eventually stagnant. After a Golden Age of peace and prosperity, internal crises again arise. At this point there appears, for the first time, a moral and physical weakness which raises, also for the first time, questions about the civilization's ability to defend itself against external enemies.

Racked by internal struggles of a social and constitutional character, weakened by loss of faith in its older ideologies and by the challenge of newer ideas incompatible with its past nature, the civilization grows steadily weaker until it is submerged by outside enemies, and eventually disappears.

When we come to apply this process, even in this rather vague form, to our own civilization, Western Civilization, we can see that certain modifications are needed.
https://exploringrealhistory.blogspot.com/2020/02/part-1-tragedy-and-hope.html