Explain what dichotomy is and what the dichotomy was in the 1920s between modern and traditional ideas. Explain how World War 1 left America in a...

A dichotomy is a tension between two concepts that are opposites, or perceived as opposites. Dichotomies are found all over the place; some are true dichotomies---they really are opposites that basically exhaust the options---while others are false dichotomies---they may be mutually compatible, or there are other alternatives not being considered.

An example of a true dichotomy is even versus odd numbers. Every integer is either even or odd, by definition. There are no exceptions and nothing in-between.

An example of a false dichotomy is male versus female. There are a number of intermediate states, as well as many species that have no sexes or more than two sexes.

Shortly after WW1, the US and Europe went through a period of deep disillusionment. Prior to the war, there was a general sense among both intellectuals and the public at large that the world was getting better, that modern ideas and technologies were finally solving the world's problems and bringing us toward something greater, perhaps even a utopian future.

The war destroyed that vision; as the bloodiest single conflict in human history up to that point, it made people feel as though all of this progress was a dangerous illusion, which only served to amplify the inherent violence and treachery of human nature with fancy new technologies like tanks and machine guns.

Thus, there was a profound tension in people's minds---a dichotomy---between wanting to embrace the hope that technology and modernity offered us, and wanting to give it all up and go back to a time that was perceived to be more peaceful and moral.

We are fortunate that humanity ultimately chose to embrace modernity. In fact, even if you include the World Wars, total rates of violence in the world have been declining for centuries. Despite two depressions and many recessions, our standard of living has risen by a factor of 20 in First World countries since this period of disillusionment. We aren't in a utopian future (yet?), but in most ways the world really is getting better over time.