Now two Pennsylvania researchers have put worship to scientific scrutiny and found in the recesses of the brain evidence of a "machinery of transcendence" that gives the faithful a glimpse of the divine.
Using high-tech imaging techniques to chart brain activity during spiritual experiences, Andrew B. Newberg and Eugene D'Aquili zeroed in on portions of the brain and concluded that God may actually be hardwired inside our skulls.
"Science has surprised us," Newberg and D'Aquili write in Why God Won't Go Away: Brain Science and The Biology of Belief. "Our research has left us no choice but to conclude that the mystics may be on to something."
The authors are adamant that their findings do not purport to confirm the existence of God, but, remarkably for scientists, they do not rule it out.
"This has made us somewhat unique," Newberg said in an interview. "We hope to encourage people, the layperson if you will, to explore their own feelings and beliefs about religion and science, and deepen their understanding of both."
Newberg, an assistant professor of radiology at the University of Pennsylvania School of Medicine in Philadelphia, and D'Aquili, associate professor of psychology at U. of Penn. until his death in August 1998, spent nearly six years researching brain physiology for the book.
They have compiled data using radioactive dyes to trace clusters of activity in the brains of praying Franciscan nuns and Tibetan Buddhists in meditation, capturing images while subjects were at the height of religious devotion.
This SPECT (single-photon emission computed tomography) imaging allowed them to pinpoint areas of neuronal activity during spiritual experiences. When combined with existing science that links specific functions to specific locales of the brain, the authors say, these experiments have major implications for how we understand world religions, myth, ritual and mysticism.
Perhaps Newberg and D'Aquili's most startling finding: Parts of the brain said to be responsible for defining the borders between the self and the world seem to change dramatically in those approaching deep spiritual states.
Brain scans indicate that worshippers have their sense of self gradually wiped away or made limitless, and they seem to experience a sense of infinite space and eternity, or a timeless, spaceless void.
This, of course, coincides closely with the sensations commonly described by those recounting their feelings when prayer or meditation brings them closer to God or a higher reality.
The scientists go further. In monitoring two small areas of the cerebral cortex, called the attention-association area and the orientation-association area, they noticed varying degrees of this selfless, spaceless and timeless sensation, implying a spectrum as worshippers move deeper into spiritual experience.
At the endpoint of this spectrum, they contend, is a "state of pure mind, of an awareness beyond object and subject," which they call "Absolute Unitary Being."
Newberg and D'Aquili speculate that all world religions may trace their origins back through culturally diverse interpretations of this same mental state.
"All religions, therefore, are kin. None of them can exclusively own the realist reality, but all of them, at their best, steer the heart and the mind in the right direction."
And, the authors contend, the evidence suggests the brain does not invent this supreme religious state, but instead finds it.
Standard thinking among most psychologists and sociologists, the authors say, has been that religion arises from "a cognitive process, based on faulty logic and incorrect deductions: In very simple terms, we feel fear and we long for comfort so we dream up a powerful protector in the sky.
"A neurological approach, however, suggests that God is not the product of a cognitive, deductive process, but was instead 'discovered' in a mystical or spiritual encounter made known to human consciousness through the transcendent machinery of the mind," they write.
First published by Ballantine Books in 2001 to widespread media coverage, the book was re-released in April 2002 with a new epilogue. Written with freelance author Vince Rause, Why God Won't Go Away is among the first mass-market books dealing with the new field of neurotheology, which blends studies in neurology and theology.
The two have not mixed well; science traditionally has viewed mysticism as the product of deluded or distorted minds. The revelations retold by Islam's Mohammed, the religious visions of the Catholic mystic St. Teresa of Avila and the conversion experience of Mormon prophet Joseph Smith have at times been ascribed by scientists to illness or seizure.
But research indicates far from malfunctioning, the human mind is instead "mystical by default," write Newberg and D'Aquili.
"We believe this sense of realness strongly suggests that the accounts of the mystics are not indications of minds in disarray, but are the proper, predictable neurological result of a stable, coherent mind willing itself toward a higher spiritual plane," they write.
Brain physiology also may reveal much about how religious myths are formed and account for why, as noted by scholar Joseph Campbell, the myths of separate cultures have been strikingly similar throughout history.
Newberg and D'Aquili contend that creation of these common patterns of myth -- virgin births, expulsions from paradise, dead and resurrected heroes -- stems from applying to higher questions the same brain tools that humans use to make sense of the physical world.
Much of it is a survival mechanism. As it often does with earthly challenges, the brain reacts to human existential fears by reducing them to systems of opposites -- man vs. leopard, life vs. death, heaven vs. hell, good vs. evil. Explanations that reconcile such opposites bring relief, even elation.
These breakthroughs, the authors say, are then reinforced by positive emotional responses sparked by the brain's primitive limbic region, which controls emotion.
"We believe that all lasting myths gain their power through neurologically endorsed flashes of insight," they write.
Cross-cultural similarities in rituals also may have origins in the brain. Rhythmic noises, repetition of phrases, such as mantras or prayers, extraordinary physical gestures and even certain smells seem to draw reactions from parts of the brain that trigger spiritual feelings, the authors write.
"When religious ritual is effective, and it is not always effective," they write, "it inclines the brain to adjust its cognitive and emotional perceptions of the self in a way that religiously minded persons interpret as closing the distance between the self and God."
In its own way, Why God Won't Go Away seeks to bridge the gulf between faith and science. It is part of a larger trend of interdisciplinary study that increased markedly in the last decades of the 20th century in fields ranging from cosmology, quantum mechanics and biology to mathematics and medicine.
That may account for some of the criticism the book has received. While some have called it "groundbreaking," critics have faulted it for being neither a work of philosophy or a linear scientific treatise. One called the book a hybrid, "with something in it to offend everyone."
Some atheists have welcomed the book to the extent that it relegates religious experience to pure biology, which it only partly does. But they also feel the authors have demonstrated a bias in favor of religion.
Nor are all of the book's assumptions about how parts of the brain work widely accepted by the scientific community.
"This is a fascinating field that needs to be entered with extreme caution and a rigorous scientific approach," Pietro Pietrini, a professor of clinical biochemistry and psychiatry at the University of Pisa in Italy, said of the book in an April 2001 interview with WebMD.
"Anything we do or feel, from a simple activity like moving a finger to the deepest passion like love or rage, has its own characteristic pattern of brain activity," Pietrini said.
In the new epilogue, Newberg and D'Aquili acknowledge the controversy.
"One of the goals of our work, and the message we've tried to communicate in this book, is that science and religion do not have to be incompatible," they write. "One need not be wrong for the other to be right."
August 10, 2002--To those who believe, prayer can be a mysterious distillation of adoration, gratitude, pain and hope. Science prefers what is "real," and thus subject to measurement, analysis and explanation.