Wray Herbert is the author of "On Second Thought: Outsmarting Your Mind's Hard-Wired Habits."

Midway into this ambitious, erudite volume, science historian and professional skeptic Michael Shermer relates this intriguing personal story: In 2014, his fiancee (now wife) Jennifer Graf had moved to California from Germany, bringing with her a Philips transistor radio, a gift from her late and beloved grandfather, Walter. Walter had been a surrogate father to Graf, and she had fond memories of listening to music with him, but the radio wasn't working. She and Shermer switched out the batteries, tried various stations and otherwise fiddled with the machine, but in frustration ended up tossing it into a desk drawer in the bedroom.

Months later, following a small wedding ceremony at their home, Graf was feeling melancholy and disconnected from her family. The newlyweds took a quiet moment together, away from the group, and at that precise moment music started wafting from the bedroom. They followed the sound, which was a love song, and traced it to the desk drawer, indeed to the "broken" radio. It was, Shermer recalls in his book "Heavens on Earth," a "spine-tingling experience."

And it gets better. The radio could have been tuned to any station, or to no station at all, but it was playing just the kind of emotionally comforting music the couple needed at that moment. The radio continued to broadcast similar music all evening, then went silent. It has remained silent since, despite Shermer's efforts to revive it.

What are we to make of Shermer's "spine-tingling experience?" What does Shermer make of it, long after the fact? He is a trained scientist and, more important, a devoted skeptic who has built a career debunking any and all claims of the paranormal. Yet by his own account he has difficulty dismissing this extraordinary experience as a psychic anomaly. The physics of the radio suddenly playing might be easily explained — a change in humidity, a speck of dust, whatever — but the timing and emotional significance of the experience are uncanny, and indeed impossible to explain with the scientific insights available to us now.


“Heavens on Earth,” by Michael Shermer (Henry Holt and Co./Henry Holt and Co.)

Shermer devotes considerable space to this personal story, as I have here, because it encapsulates the human condition. Ever since the earliest humans became aware of their mortality, they — we — have been striving to make sense of the big chill and what comes after. Death is undeniable, yet unknowable, a mystery that eludes our intellect, so we must come up with ways to make it all meaningful, something more than nothingness. This dilemma leads inevitably to explanations — beliefs — that include immortality, the soul, resurrection and, most important here, heaven.

Consider the vocabulary we humans have invented for heaven: the afterlife, Arcadia, dreamland, Eden, Elysium, hereafter, kingdom come, paradise, land of milk and honey, nirvana, Shangri-La, Zion. By any other name, Shermer writes, heaven is "the empyrean residence of gods and other preternatural essences — angels, demons, ghosts, souls — that have, to append a few common idioms, transcended, crossed over, passed through, passed away, given up the ghost, or gone the way of all flesh from the here and now into the hereafter." The belief that death is not final is overwhelmingly popular: Since the 1990s, the Gallup polling organization has consistently found that about 3 in 4 Americans believe in heaven of some kind. A survey of people in 23 countries found that more than half of respondents believe in an afterlife. So pervasive is this conviction that even a third of agnostics and atheists proclaim belief in an afterlife.

Shermer acknowledges that some believers draw solace and sustenance from their belief in heaven and that they require no proof. But as a professional skeptic, he thinks it's important to put these powerful and pervasive ideas to the test, with the same rigor that one would use with ESP or alien abduction. Approximately 100 billion humans have come and gone since the beginning of time, he notes, and not a single one has returned to confirm the existence of an afterlife, "at least not to the high evidentiary standards of science."

The core of "Heavens on Earth" does just that, bringing the high evidentiary standards of science to bear on heavenly claims. Shermer examines the claims of spiritual seekers, who see consciousness as primary, an essence from which all human experience is derived. He tries to take these views seriously — especially those of his friend and intellectual rival Deepak Chopra, the most prominent American proponent of these ideas. He even attends a conference and meditation training at the Chopra Center in California. But in the end he is critical of Chopra's lack of rigor, dismissing his writing and thinking as "gobbledygook" and "pseudo-profound bafflegab."

He also essays the claims of those who have documented near-death experiences, especially those who use these anecdotes as evidence of afterlife and resurrection. As intriguing as these reports from beyond may be for some, their characteristics — the out-of-body experiences, the bright lights and dark tunnels — can be better explained by neuroscience than accepted as miracles. Shermer is similarly dismissive of other psychological anomalies that have been offered and taken as evidence of reincarnation and time travel, among other phenomena. He includes his own radio experience with these unconvincing proofs of the paranormal.

So what did happen on the evening of the wedding ceremony, when Graf's grandfather, Walter, seemed to comfort her from the great beyond? For an answer, Shermer turns to the sci-fi film "Interstellar," in which the hero passes through a wormhole and saves humankind by communicating through portals from another dimension. It's a far-fetched plot — and a bizarre explanation for the well-timed love song — but Shermer argues that it's at least grounded in natural law and forces. What if grandfather Walter exists in another dimension, where he can see Graf at all times of her life simultaneously and use gravitational waves from a near wormhole to turn on his old radio?

Okay, so this is wild speculation. We don't yet have the science to explain spectacularly unlikely events. But until we do, Shermer says, we don't have to fill in the explanatory gaps with gods and preternatural forces. Instead, he concludes: "Revel in the mystery and drink in the unknown. It is where science and wonder meet."

Heavens
on Earth
The Scientific Search for the Afterlife, Immortality, and Utopia

By Michael Shermer

Holt. 305 pp. $30