So there's that change of general consciousness, and then there's this boom after the war, this expansion into the West. It was like the 1950s. The American economy was pumping at top speed. The kinds of people who would move into these communities and organize their lives around a utopian dream now had dreams about the West.

They [Rappites] were moving from Southern Indiana to Pennsylvania, where they had originally settled when they came from Germany. They were looking for someone who wanted to buy a pre-built town, which wouldn't have been appropriate for any kind of normal settlement. That's when Robert Owen [Welsh industrialist and utopian socialist] buys the village and founds New Harmony.

The Jacksonian era is generally talked about in terms of individualism, and the development of free market capitalism, and Victorian prudery. It was shocking to find a parallel history to that - a bunch of Americans with very different priorities. I stumbled on to these people, and then became completely fixated on them. The question that drove me was: how did these reasonable people adopt these extremely unreasonable ideas?

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.

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.

Utopians don't say, 'The world's corrupt, women make less money, people of color are oppressed at every turn.' You don't list the problems of the world; you describe a world in which those things aren't the case. The critique is implicit and as a result it's kind of a positive critique. You're not listing what's bad, but rather what would be good - you're oriented toward this positive vision.

Atheist isn't really the right word because they tended to believe in some sort of Enlightenment, capital 'N' Nature kind of god. But these were people who in their times were criticized as infidels.