The thought was, 'We're going to go to California, where the soil is black and ten feet deep, and there are no rocks, and there's gold in the hills.' The West becomes the surface onto which people project their fantasies, where once the future had been the place they projected their fantasies. So it's not just the war that ends the utopian communities, but what follows.

The vision shared by both [French utopian] Charles Fourier and Robert Owen was for an entire town to fit into one structure. Owen's design for what he called a "parallelogram" was essentially to have a whole city in one building, laid out around a huge quadrangle. Fourier's scheme was to build a massive Versailles-like structure that he called a "phalanstery." In both cases they had these architectural dreams that we now recognize as pretty unappealing.

The thing that had fueled these utopian communities was a literal belief, and not just a general sense of optimism, that the earth was about to become a paradise. That idea cannot hold water after the war.

Some people think God is going to guide those humans. The Oneida community and the Shakers both believed that they had received revelations about how to build the New Jerusalem that the Bible says is coming

Some people just think utopians are idiots who are imagining rivers of candy and not really engaging with the world's ills, and sometimes that's surely the case, but I think that imagining the perfected society is a way of expressing your disgust with the current state of affairs.

Because the utopian's worldview was framed around moving toward this perfected future, it helped stimulate the private exertions that add up to social progress. Progress is work. People need to build things and sacrifice and have a harder life for things to get better. On its own, I don't think even the most brilliant critique stimulates that kind of effort as well as an appealing vision of the future.

The fatal flaw of most utopian visions is that they're fundamentally static, and that's not a comfortable place for humans to live. Fourier was very good at imagining a utopia that is constantly changing and very busy, but a vision of paradise that would have been most tantalizing to an underfed overworked factory worker in 1840 doesn't have much appeal in fiction because it's not a story.