No one foresaw today's astounding surge of interest in spirituality more accurately than the late Abraham Maslow, founder of humanistic psychology, one of the principal architects of the human potential movement, and my colleague as an editorial adviser for Psychology Today during the last three years of his life. When we have shelter, get enough food, and acquire a layer of financial security, Abe argued more than 30 years ago, these "A Values"--basic survival needs--no longer monopolize our passions. We upgrade our priorities from animal needs to spiritual concerns such as altruism, art, and literature--what Abe called "B Values." We even develop a yearning for ecstatic highs, "peak experiences," as he called them. In our long private talks, Abe jokingly referred to these B-Value hungers as "higher grumbles."

Abe warned me that such a shift in individual and cultural priorities might not come off peacefully. Serious redefinitions of who we are tend to get bloody--as the Protestant Reformation sometimes did. But neither Abe nor I foresaw how today's spiritual searchers would frighten fundamentalists of all faiths into a firestorm of angry and terrified reactions. We didn't expect today's bumper crop of faith-driven terrorists or the current holy wars over religious issues such as abortion.

Abraham Maslow saw better than anyone else the price we pay for the separation of spiritual concerns from the rest of intellectual life, a great divide frozen into place by centuries-old wars between science and religion. Abe hated modernity's artificial divorce of facts from values, medicine from health, the material from the ideal. "Isolating two interrelated parts of a whole from each other, parts that are truly `parts' and not wholes, distorts them both, sickens and contaminates them," he wrote. He raged against shrinking the poetry of the human person down to a psychological disease or a molecular accident. He believed in beauty, if only as a reason to get up in the morning.

Abe blasted Western science, especially "value-free" social science, for cutting itself off from aesthetic and spiritual concepts such as beauty and ecstasy, just as religion was walling itself off from scientific study on the other side of the great divide. A rigorous research methodologist, he insisted that scientific method could be used to probe not just the mysteries of the body but the deeper dimensions of the embodied soul.

It's taken me years to grasp what Abe was teaching me. And that understanding has come mostly during the last four years as mind-body research has knocked holes through the artificial firewall between medical and spiritual practices. Both scientists and theologians were once committed to the strict separation of science and religion. Scientists wanted to own all truth in the physical world, while preachers claimed to be the sole arbiters of all questions of faith and morals. But Maslow saw how that dichotomy flattened the intellectual landscape. In their artificial separation, the physical and the spiritual never had to humble themselves to deal with the challenging overlap between each other's kingdom of truth. It's like isolating women and men into separate domains, whereas "they need each other in order to be themselves," Abe always said.

The coming together of science and spirituality started slowly in the medical profession. Harvard cardiologist Herbert Benson showed that repetitive prayer--a standard practice in most faiths--produces a "relaxation response" that reduces stress-related damage to the heart and other organs. In dozens of rigorous experiments, Benson's research teams used meditative prayers--a disciplined way to listen to the spirit within--to generate significant reductions in hypertension, heart attacks, infertility, and other common ailments, while also improving memory, mood, and even the level of skin moisture. The prayers also controlled arthritic pain, the physical and emotional discomforts of premenstrual syndrome, and most other body agonies. People who prayed had medical bills 36 percent lower than those who did not, the researchers found. In addition to the relaxation response, Benson concluded from his data that among those who prayed, a healing power of belief, a "faith factor," was at work.

Other medical researchers have continued Benson's work in testing the effects of spirituality on physical health. At the National Institutes of Health, research psychiatrist David Larson began to doubt the Freudian principle that religion is uniformly pathological. Poring over 2,348 psychiatric studies, he found that only three had focused on religion as playing any major role in the subjects' mental conditions. In fact, as he dug into the records of studies treating religion as an incidental variable, he found that in 84 percent of them, religion turned out to correlate positively with physical and mental health. In only 3 percent of the studies did religion correlate negatively with health, while the correlation was neutral in 13 percent of the studies. Larson raised private money to set up the National Institute of Healthcare Research in Rockville, Maryland, which then conducted a number of studies on the rich interaction between spirituality and health.