But there are people who regularly think about the divine in this physical way. Especially in more experientially oriented evangelical Christian communities-called "renewalist"-people expect to have a personal relationship with God. They go for walks with God, have coffee with God, ask God what shirt they should wear in the morning and even what shampoo they should buy. They expect God will talk back.

This is no fringe phenomenon. In 2006, the Pew Foundation reported that 26% of Americans said they had had a direct revelation from God. A few years earlier, Gallup reported that about the same number had heard a voice or vision as a result of prayer. Rick Warren's "Purpose Driven Life" sets out to teach people how to know God as a best friend. It has sold more than 30 million copies, making it the best-selling hardback book in American history apart from the Bible.

Religious leaders teach people how to identify thoughts and images in their mind that they should treat as God's communication to them. Looking at your closet and asking God whether he'd prefer the black shirt or the blue one is a way congregants practice this identification.

Among renewalist evangelicals I spoke to during a decade of research, I often encountered people who felt a little foolish about this at first. As one man remarked about his first real attempt: "I thought, 'I have lost my marbles. I am actually talking to the ceiling and thinking that that will do something.'"

And yet people also report that when they pray in this way, they begin to experience God's presence in a personal way, something that is comforting and empowering. Research, including my own, shows they tend to be less stressed and less lonely than others.

The God among the congregants in these churches is magically real. They didn't treat God as different from the stuff of the material world-tables, chairs, other people. They talked about God saying, telling, prodding, encouraging, as if he were right there at the dinner table. And sometimes they put out a place setting.

Of course, people can't actually see God at the dinner table. Those who put out a place setting know that they are using their imaginations to make God feel real. That allows them to treat their belief in God as a deliberate choice in the face of uncertain knowledge.

That's important, because evangelical Christians doubt, too. Doubt is part of the experience of faith: As the apostle Paul put it in Corinthians, "we see through a glass, darkly." People doubt that they understand God rightly; they doubt that the promise of joy they hear from the pulpit really applies to them. And in a world in which they know wise, good people who do not share their faith, they may doubt divinity itself. A man I met at the Vineyard Christian Fellowship, the church I studied, put it this way on his website:

"If there is a God . . . What an incredibly mind-blowing thought-a thought that every human being should wrestle with at least once every few hours . . . I wake up every morning trying to bridge the gap between these two worlds-the world of what is imagined and the world of what is real. Most of the time I fail miserably. But once in a while, not very often, these two worlds collide beyond my wildest dreams. And it makes me imagine, again, 'what if . . .'"

The man who wrote this believes in God. But he cannot escape his doubt because he knows smart, sensible people who do not believe in God. Envisioning God as a magically real presence is not so much foolish as it is a way to make the divine seem real in a skeptical, modern world.

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Ms. Luhrmann is the author of "When God Talks Back: Understanding the American Evangelical Relationship with God," just out from Alfred A. Knopf.