In Age of Empire, chapters 10 through 13, Hobsbawm paints a clear picture of what society looked like in the decades before the Great War. We find that in the belle epoque (roughly 1874-1914) religion began to play a lesser role in the western countries, science was on the rise and rising quickly, the industrial class was controlling industry as always, and nations were flexing their muscles economically and militarily. This new nationalism was also expressed through the new sciences, where scientific innovation meant national progress.
Hobsbawm says that nationalism and imperialism largely caused the First World War. Economics, which is definitely connected to nationalism, played a big role as well: the imperial nations were jockeying for new lands to take over and new markets. This led to heightened tension between the rival powers. Since each power was so built-up militarily, they each thought that, if they ever had to use force to compete with other powers, they would win easily. Hobsbawm gives examples where this tension almost exploded into war even before 1914: affairs in Morocco and Egypt, as well as elsewhere. On 28 June 1914, a Bosnian-Serb student assassinated the Archduke of Austria in Sarajevo, Bosnia; there is no doubt that the assassination was a result of imperialism. Austria-Hungary declared war on Serbia one month later. Russia, ally to Serbia, mobilized their forces. Germany, Austria-Hungary's ally, quickly mobilized their army. France, in response, mobilized theirs. Germany declared war on Russia. France, ally to Russia, declared war on Germany. Germany, invading France, went through Belgium. Britain, Belgium's ally, declared war on Germany...
We see here, in the months prior to military engagement, that one of the worst wars was started over something so trivial (assassinations happened all the time), and that the great European powers, "bound by allegiance", were so eager to enter the fray. Little did they know that their swift choices would lead to one of the greatest disasters in world history: the technological advancements in military technology would prove devastating. Hobsbawm did touch briefly on the cultural and societal causes of the conflict, but mostly he wrote about the diplomatic and economic causes in chapter 13. Here are some other insights*:
As Nietzsche philosophized (with a hammer), the moral fabric of European (or Western) society was shredding in the period of the belle epoque; the growth of science, nationalism, aesthetic-based art, and capitalism all caused the slow decay of morality. Nietzsche's The Gay Science is a perfect illustration of his thoughts on the matter: there is a scene when a "madman" wanders into a village market asking, "Where is God?" Several young scientists and atheists in the village market poke fun at Nietzsche's madman, and ask him if he has lost his god. The madman replies, "God is dead... And we have killed him. How shall we comfort ourselves, we murders of all murderers?" Aside from being very misinterpreted, Nietzsche uses this passage to illustrate that society--with its new sciences, technologies, economies, and arts--has lost its faith in the thing that had once held people and morality together. By saying "God is dead" Nietzsche's madman gives a warning to 20th century society: if there is no objective truth or morality, then nations begin to fill that void with nationalism, and this leads to conflict and war, as we have sadly seen.
An example of this new nationalism in literature, we can look to Robert Graves' Goodbye to All That: An Autobiography. "...[L]et me at once record my... earliest memories. The first is being loyally held up to a window to watch a procession of decorated carriages and waggons for Queen Victoria's Diamond Jubilee in 1897." We can also look to Ernst Junger's Storm of Steel: "We had come from lecture halls, school desks and factory workbenches, and over the brief weeks of training we had bonded together into one large and enthusiastic group. Grown up in an age of security, we shared a yearning for danger, for the experience of the extraordinary. We were enraptured by war." This is the way the 20th century started. Parallels can be drawn between the beginnings of the 20th and the 21st centuries. Are these parallels worthy of a second look? Is today's international society similar to that of the belle epoque (or the antebellum of WWI)? Are we in an antebellum today, a "before the war"?
*See Modris Ecksteins, The Rites of Spring: The Great War and the Birth of the Modern Age. And Paul Fussell, The Great War and Modern Memory.