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.

One of the things that's amazing about reading the private writing of these folks is that they enthusiastically describe things which we have now seen, and which are widely regarded as unappealing. They'll write, "It's going to be beautiful, we're going to have a town of 1,000 stone buildings that are all identical." And we as modern readers think, we've seen that; that's bad Soviet architecture or a public housing project. Nobody fantasizes about living there.

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.

The Enlightenment faith that things are getting a little bit better each decade becomes difficult to support. People recognized that there had just been a war that was worse than the war of 1812, and worse than the Revolution; things were clearly not getting better and better.

I worry that I may have overstated the impact of Civil War on the utopians. By the time the Civil War comes, most of the communities were quite separated from the wider American society. Their rhetoric is still about transforming the world, but they're not having that much traffic with their neighbors.

Margaret Fuller was already a celebrity, travelling around the world. Emerson, who was the axis around which that whole community turned, just didn't like Fourier's ideas very much. He thought it was all too rigid and programmatic. He said, "Fourier had skipped no fact but one, namely life." He thought it was an inhumane system - the day is scheduled too precisely. He didn't think it would work, and he was right.

That to me was one of the most exciting, and weird puzzles of this book: how are the most religious people and the least religious people of their time all drawn to very similar visions of utopia?