They're people who probably imagine that they would have had a better time in the past. I wouldn't imagine you'd encounter a lot of black people saying 'Oh, the '50s, that was when America was great.' It's very dangerous because the past was imperfect, and you can't go back anyway.

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.

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.

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.

But if you'd only ever lived in small wooden house in the middle of wilderness, it sounded much better. Especially because it provided intense community, and these people lived in incredible isolation.

The secular utopians basically said the exact same thing, they just took the Bible out of the equation. The religious and the secular groups recognized each other as fellow travellers. They exchanged newsletters and asked each other questions like, "What's a good soup pot to use if you're making dinner for 800 people?" They had these practical connections.