The story I tell in this book is how they solve this problem. It is a kind of detective story. I set out to pick up and piece together clues about the way ordinary people living in a pluralistic, scientific society come to experience—to some extent—a God that is as present to them as Christ was to Mary Magdalene when she came to tend him in his tomb. Like all stories, it is told from a particular point of view.

I call this point of view the anthropological attitude. Anthropologists are taught as students to seek to understand before we judge. We want to understand how people interpret their world before passing judgment on whether their interpretation is right or wrong. And so I will not presume to know ultimate reality. I will not judge whether God is or is not present to the people I came to know. Yet I believe that if God speaks, God's voice is heard through human minds constrained by their biology and shaped by their social community, and I believe that as a psychologically trained anthropologist, I can say something about those constraints and their social shaping. The person who hears a voice when alone has a sensory perception without a material cause, whether its immaterial origin is the divine presence or the empty night. Only some religious communities encourage people to pay attention to their subjective states with the suggestion that God may speak back to them in prayer. I will ask how a church teaches people to attend to their inner awareness and what training in prayer and practice they provide—and I can answer that question. Only some people have those startling, unusual experiences (although more people, it happens, than most of us imagine). I will ask whether some people are more likely to have those experiences than others, and whether there are differences in temperament or training that might set those who are able to have such experiences apart from those who don't—and again, I can answer that question.

But the anthropological attitude demands humility, and there are questions I cannot answer. In Michelangelo's Genesis, man reaches out for God, and God for man, and their fingers do not quite touch. An anthropologist can describe only the human side of that relationship, the way humans reach for God. I can describe the way a church can teach congregants to pay attention and learn to use their minds to help them make their experience of God real and concrete; I can describe the practices they develop, and the way they learn those practices and teach them to each other. I can describe what we know of the psychological mechanisms through which the mind can sense the presence of something for which there is no ordinary sensory evidence and the way those mechanisms are different from psychiatric illness. But my methods cannot distinguish between sensory deception and the moments when God may be reaching back to communicate through an ordinary human mind.

We see through a glass darkly. There is much we do not know, even now, about spiritual experience. I can take up Paul's problem about knowing when God is truly present, but I cannot solve it. The goal of this book is simply to help readers understand the problem of presence more deeply, to understand why it is a problem—why it can be hard for Christians to know when God has spoken—and to explain how, in this day and age, people are nonetheless able to identify that presence and to experience it as real.

Excerpted from When God Talks Back by T. M. Luhrmann. Copyright © 2012 by T.M. Luhrmann. Excerpted by permission of Knopf, a division of Random House, Inc. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.