The western civilization doesn’t exist in realty; it’s an abstract concept developed by the French philosophers during the Age of Enlightenment. These philosophers were of the view that human progress must have a single civilization as its goal—and to this civilization they gave the name “western civilization.” But their conception of the western civilization consisted of only the developed regions of the world—countries like France and England, and some parts of Germany, Italy, and America were included in it; rest of the world, they posited, was populated with barbarians who must be subdued in the name of human progress.
For much of last 2500 years, no one in Europe thought in terms of a western civilization, because there was no feeling of unity among the Europeans—they were always at war with each other. Ancient Greece regarded Sparta as its enemy. The Roman Republic regarded Greece as its enemy. The history of the Roman Empire is the story of the wars that it fought with the barbarians in Northern Italy, Germany, Spain, England and other parts of Europe. Spain, for much of the Middle Ages, was an Islamic kingdom. By the time of the Renaissance, most parts of Europe acquired a common religion but there was no end to the European wars.
After the Enlightenment, the idea of western civilization remained locked inside the books of philosophy and history and had no impact on the politics of major European countries. In the 20th century, the Europeans fought two great wars—the First and the Second World Wars—in which they slaughtered millions of their own people and reduced large parts of Europe to rubble. In the bloodbath of the two wars, it was impossible for the European nations to conceive of themselves as a part of the same western civilization. The Second World War led to the division of Europe into two blocs — the free bloc and the Soviet bloc. The free bloc nations started identifying themselves and other nations that were opposed to the Soviet Union as the western civilization.
The fall of the Soviet Union in 1992 is seen as a victory for the western civilization, but the truth is that the Soviet Union was ruled from Moscow, an European City; it had a western ideology, communism; it enjoyed the strong support of several European intellectuals—therefore, I think, it is logical to see the collapse of the Soviet Union as the failure of one faction of the western civilization. The geographical extent of the western civilization is a controversial subject because its political, linguistic, racial, and religious character is not clear.