Early in his book, The Modern Mind: An Intellectual History of the 20th Century (2001), Peter Watson divides the century into four parts, each determined by a change in its shared sense of the future.
1. 1900-1914. In 1900, the dominant sense was one of optimism. Dramatic changes were taking place in society, with new methods of transportation and communication; and in culture, in both the arts and sciences. These changes gave the impression that the future of society and culture would be different and better than in the past. People shared the sense that history was a story in which a growing number of people would actually live better than their parents had.
2. 1914-1945. The war of 1914-1918 shattered this dominant shared illusion of progress. Pessimism became the dominant mood.
3. 1945-1973. With the defeat of Germany and Japan, once again positive change seemed certain. This period was “perhaps the most positive moment of the most positive hour” (7) of the 20th century.