Preface

"The greatest obstacle to discovering the shape of the earth, the continents, and the ocean was not ignorance but the illusion of knowledge."

Daniel J. Boorstin, The Discoverers: A History of Man’s Search to Know His World and Himself 

Religion is a fascinating mystery. Why does the idea of an invisible but omnipotent God have such a powerful grip on the human mind? Why do such beliefs motivate both selfless generosity and mindless hatred? Why do people think of God as vengeful, judgmental, and punishing, yet also unconditionally loving? Why does a discussion of religion tend to ruin an otherwise pleasant conversation? Why is religious belief special, unusual, and tenacious? Humans have invented thousands of provincial and mutually contradictory religions, each with adherents absolutely certain of the truth of their own unique brand of magical, spiritual, or supernatural revelation. This fact alone strongly suggests that mysticism arises not from the efforts of an infinitely wise and powerful deity to reach us, but from something intrinsic to human nature. What is that something, and what is it about our peculiar ecological niche that led to its evolution?

Although my study of religion began with my first Sunday school class at age four, I did not begin asking such questions until I was in high school. By the time I was studying neuroscience in graduate school, I had formulated some incomplete but personally satisfying answers, and in my more self-indulgent fantasies even imagined publishing them someday. Many years later those answers were clarified by what most believers would call a mystical or religious experience, a description of which appears at the beginning of chapter 1. It was not my first such experience, but it was so vivid and intense that it left me with a feeling of great empathy for believers. I had experienced that compelling sense of presence that is often interpreted as the presence of God. Ironically it also left me feeling that I should not write this book, because, although more convinced than ever that this sensed presence was an illusion, I had learned how comforting the illusion can be to someone who really needs it.

Two months later all of that changed. Suddenly the dark side of religion became manifest as crashing jets, burning buildings, and mass murder, and the need for understanding seemed urgent. In the years that followed, prominent New Atheist authors retaliated in words. Part of their message was a much-needed proclamation that the unclothed emperor has a dangerously warped sense of morality, but several of them also tried to explain religion as a natural phenomenon. Meanwhile authors in the pop-science genre of neurotheology attempted another kind of explanation of religion, in some cases clearly in reaction to the New Atheists.

All of these books were missing something important. The New Atheism books were rousing and delightful reading for nonbelievers, but they largely ignored the real reason that most believers believe: their personal experience of the presence of God. By contrast, some studies in the neurotheology literature tried to get at that ephemeral sensed presence, but mainly at a mechanistic level, often with too few subjects and inadequate controls, and sometimes with no clearly specified hypothesis to test.

I felt I had something useful to contribute to the discussion and so began to write. After several difficult years I discovered that I was really writing two books: one that tries to explain why humans are prone to feel the illusion of God’s presence, and another that tries to explain how we feel that illusion. This book, the first of the two, deals mainly with the behavioral and evolutionary biology that underlies religious and spiritual emotions in humans, with special emphasis on the feeling of a sensed presence. The second book, which I will sometimes refer to as the sequel to this one, is still in progress at present. It explores the neurobiology of mystical experience, guided not by mysticism, but by the ethological hypothesis developed in this volume. A few of the most important ideas developed in the sequel appear in condensed form in chapters 12 and 13 of this book. I have tried to make both books accessible to the general reader, but the neurobiological sequel is unavoidably more technically demanding.

In the first chapter of this book, I define the kind of religious experience I seek to explain, and I present some typical examples. In chapter 2, I explain why I am not satisfied with the believer’s interpretation of the sensed presence. In chapter 3, I summarize prominent naturalistic explanations of religious belief, and I define several important biological concepts that I use in subsequent chapters. I emphasize that religion is a complex and multifaceted thing and that we should not expect any one idea to explain it all.

I present my own explanation for the feeling of a mystical presence in chapter 4. I suggest that highly emotional religious experience of this kind arises indirectly as a natural consequence of a biological adaptation. Although that adaptation is specific to the peculiar ecological niche we humans occupy, analogous adaptations can be seen in many other animal species. I argue that religious emotions are neither as supernatural in origin nor as uniquely human as commonly assumed.

The rest of the book deals mainly with the questions raised by my hypothesis, the evidence that supports it, the predictions it makes, and the possibility of testing those predictions. Along the way, it sheds light on several vexing religious puzzles, like the power behind fundamentalism, the growing preference for personal spirituality over traditional religion, the strange allure of cults, the mysterious compulsion to pray, the special appeal of baby Jesus, the religious obsession with sex, the meaning of religious misogyny, and the greater religiosity of women relative to men. Beyond these scientific issues, the book also tries to illuminate the difficult and convoluted paths most of us must navigate in coming to terms with religion in our personal lives. This spirit permeates the book and is the central theme of its last two chapters. In chapter 14, I summarize what modern neuroscience has to say about the existence of an immortal soul. The final chapter offers an alternative way of understanding reality for readers who struggle with doubts about their religious or spiritual beliefs.

This book is not for everyone. If you have encountered crushing burdens in life, your appeal to a higher power may be a sustaining source of strength, salvation, or unconditional love. Although this book is unlikely to diminish your faith, you might not find it helpful. Others may find it helpful, but only after some special preparation. This book is about biology, and its ideas, like all ideas in modern biology, rest on the foundation of Darwin’s theory of evolution through natural selection. If you have been steeped in creationism, or even if you just feel unsure about your understanding of evolution, I urge you to start with the appendix on that subject.

For most religious or spiritually minded readers, however, the greatest challenge of this book lies in its approach to truth. How do we know something is true? How can you tell what foods are good for you, which people are your true friends, or whom you should marry? In making vital and complex decisions like these, we often get a profound feeling of knowing that seems to come from nowhere and that often proves correct. The experience is common enough that we have a name for it. Intuition is an innate and largely unconscious mechanism of the brain, a product of evolution that guides our behavior toward reproductive success, not truth-finding. An intuitive sense of certainty is useful for behavioral conviction, but it is merely an illusion of knowledge. It has impeded our comprehension not only of global geography, as historian Daniel Boorstin noted, but also of nearly every other aspect of reality. For millennia, humans have suffered and died from smallpox, typhus, tuberculosis, syphilis, measles, polio, bubonic plague, and host of other scourges that are now completely preventable, curable, or eradicated. Intuition helped in a marginal way with some of these, for example through feelings of disgust at contaminated food or dead bodies, but our intuitively appealing therapies—magical rituals, prayers to the gods, or incantations to ancestral spirits—had little effect. Eliminating these diseases required a deep understanding of the truth about how biological reality works. The requisite truth-finding mechanism was discovered and unleashed only a few centuries ago, and the way of thinking it demands does not come easily or naturally to human minds. The essence of science is an appeal to empirical evidence from the natural world as our ultimate arbiter in truth-finding, coupled with effortful, skeptical, and reflective reasoning. To see religion and spirituality in this light will be difficult for those who know by intuition—especially those who have been long committed to their faith, who have made great sacrifices for it, and whose social connections derive from it.

I wrote the book for anyone who wonders what science has to say about where religious emotion comes from, especially that powerful but ineffable longing for a mystical other. What I hope will most distinguish it from similar books is that the religious feelings I discuss will be instantly recognized by most religious readers as both familiar and essential. I expect that many of my readers will be scientifically literate and skeptical of the supernatural, but I also hope to reach a few believers who wrestle with doubt—especially young adults who are not yet so deeply committed as to be unreachable. Above all I have written it for those who genuinely seek truth and depth of understanding, wherever that journey may lead. If you are impressed with the achievements of science and disappointed with the unfulfilled promises of religion and spirituality, then read on.

Each of the first thirteen chapters builds on its predecessors, so these should be read sequentially. The last two chapters can be understood in isolation, although they also refer to earlier ones. The endnotes are mostly literature citations but include some explanatory digressions. I recommend ignoring them on a first reading. If your curiosity will not allow that, try reading them in batches as you finish each chapter. I have tried to avoid jargon, but some technical words seemed necessary. I have defined most of these where they first appear in the text, but, should those efforts prove inadequate, I strongly recommend Wikipedia. A condensed version of chapter 9 was previously published.