While these longings for God's realness are not novel in our religious history, what is new is that the experiences and practices we associate with medieval monks or impoverished snake-handlers have now become white, middle-class, and mainstream. Ordinary Americans are now embracing a spirituality that mid-twentieth-century generations had regarded as vulgar, overemotional, or even psychotic. This suspension of disbelief and embrace of the irrational makes skeptics deeply uneasy. But in fact, evangelical Christians are sharply aware of the logical contradictions that nonevangelical observers see so clearly. What enables them to sustain their commitment is a learning process that changes their experience of mind.

This book explains how this new use of the mind allows God to come alive for people. It explains what people learn, how deep the learning goes, and how powerful it is. My goal is to help nonbelievers understand this learning process. This will not turn the skeptic into a believer, but it will help to explain how a reasonable person could choose to become and remain this kind of Christian. Perhaps that will serve as a bridge across the divide, and help us to respect one another.

Let us begin by turning the skeptic's question on its head. If you could believe in God, why wouldn't you? There is good evidence that those who believe in a loving God have happier lives. Loneliness is bad for people in many different ways—it diminishes immune function, increases blood pressure, and depresses cognitive function—and we know that people who believe in God are less lonely. We know that God is experienced in the brain as a social relationship. (Put someone in the scanner and ask them about God, and the same region of the brain lights up as when you ask them about a friend.) We know that those who go to church live longer and in greater health.

So why wouldn't you believe? Particularly in this God. The major shift in American spirituality over the past half century has been toward a God who is not only vividly present but deeply kind. He is no longer the benign but distant sovereign of the old mainstream church; nor is he the harsh tyrant of the Hebrew Bible. He is personal and intimate. This new, modern God is eager for the tiniest details of a worshipper's life. He welcomes prayers about the nation, of course, but he also wants prayers about what outfit to wear in the morning. He may be grand and mighty, but he is also as closely held and precious as a child's first puppy. This God loves unconditionally; he forgives freely; he brings joy. Why would one not believe?

But the deep puzzle of faith is not why someone should believe in God. The puzzle is how: how sensible, reasonable people, living in more or less the same evidential world as the skeptic, are able to experience themselves as having good evidence for the presence of a powerful invisible being who has a demonstrable effect on their lives and are able to sustain a belief in that presence despite their inevitable doubts.

It is a problem all Christians face, although it is magnified in a secular society in which many people do not take God seriously. The problem for ordinary Christians—often surrounded by other Christians, often having grown up among good, committed Christians—is how to maintain their belief despite their skepticism: not the puzzle of why we all believe to some extent in the supernatural when we are thinking quickly, automatically, superstitiously, but the problem of how to commit to what the Bible says is true in the face of the contradictions they experience in their world. They believe—or want to believe—that the world is fundamentally good or was at least created by a fundamentally good power that is still present and responsive. Yet they see around themselves a world of great injustice. They believe, or they think that they should believe, that God loves them—and yet they don't really experience themselves, in their heart of hearts, as loved and lovable. Or they know that God wants them to love their spouse, but they can't seem to behave in a loving way. Or they sit down to pray, but they cannot persuade themselves that anyone is listening. Or they believe in God, but what they interpret as God's will has just been flatly contradicted by someone they know and trust, and now they are bewildered and confused. They believe in some abstract, absolute sense that God exists, but they struggle to experience God as real in the everyday world. They want to know how to hang on to their convictions in the face of so much evidence to the contrary, and it is sometimes very difficult for them to do so.