To counter the pervasive influence of religion in our mountain hometown, my father once loaned me his copy of Mark Twain’s satirical Letters from the Earth. A decade later I encountered Twain’s barbed commentary on a famous line from the Sermon on the Mount. To a character who claims that God would care for a poor kitten because “not a sparrow falls to the ground without His seeing it,” Twain has his skeptic respond, “But it falls, just the same. What good is seeing it fall?” America’s greatest humorist has always been its greatest skeptic. How startling, then, to find the same man so generous toward the work of spiritualist mediums in Deborah Blum’s Ghost Hunters, a portrait of 19th-century interest in what we would call the occult. In a book filled with inexplicable tilting tables, slate writing, walking bookcases, Ouija boards, séances, spirit-winds and apparitions, we read that Twain, instead of regarding such claims with cynicism, commented that telepathy “does seem to happen too often to be an accident.”

People still believe in ghosts, of course, and most of us, if pressed, would confess to experiencing the uncanny. Coincidences accumulate a little too frequently; our dreams seem smarter than our waking worlds; we feel acted upon by things we can’t explain. Twain’s own sympathy for telepathic claims stems from a premonition he had of his brother’s death in a riverboat explosion. How else could he interpret the experience than to intuit some form of supernatural communication?

If psychic activities seem exotic to us, it isn’t because experiences like Twain’s are outdated, but because so many of the narratives from the heyday of paranormal activity read like carnival accounts. Charlatans abounded in the time Blum describes, most notoriously Madame Blavatsky, who, tucked away in her Indian temple, worked tricks with secret cabinet drawers and servant-accomplices. And yet, as William James pointed out, if you are challenging the notion that all crows are black, “it is enough if you prove one single crow to be white.” Ghost Hunters tracks the effort to discover genuine white crows.

In the era that Blum portrays, science was ascendant. A kind of crown prince of knowledge, young and invested with authority, basking in astonishing discoveries and innovations, science could seem brash and even crude in its claims. John Tyndall’s perspective captures the discipline’s 19th-century brio: “We claim, and we shall wrest from theology, the entire domain of cosmological theory. All schemes and systems which thus infringe upon the domain of science must, in so far as they do this, submit to its control, and relinquish all thought of controlling it.”

The gap between the authority of religion and the authority of science was widening drastically at mid-century. In England, Darwin’s On the Origin of Species (1859) was a best seller; in America, the Civil War complicated the hope that theological reflection could guard the nation’s destiny, and perhaps rendered that hope outdated.

The expanding breach between these competing sources of cultural authority left space for an ambiguous kind of knowledge that borrowed from both. Psychic phenomena clearly laid claim to the spiritual realm of orthodox religious experience, but when James Clerk Maxwell, working out a theory of electromagnetism, suggested that wireless signals could be sent and received across great distances, science also offered a teasingly apt analogy for the “unseen paths of communication” of psychical research. It is possible to see in the popularity of psychic phenomena a triangulation of science and religion—a kind of populist third way that shrugged off older orthodoxies without abandoning religion’s spiritual vision, but that also offered itself to the empirical investigations of scientists. Champions of psychic activity, at their best, courted the imprimatur of science and the audience of religion.

What separates the time period Blum investigates from our own is the stature of the scientists and others who took psychical research seriously. Contemporaries who sympathized with the claims of mediums included Charles Richet, who went on to win the Nobel Prize for medicine; Lord Rayleigh, who claimed the same prize for physics; future prime minister Alfred Balfour; poet laureate Alfred Tennyson; and moral philosopher Henry Sidgwick. But the most impressive sympathizer was William James, who wrote the most important text on psychology in 19th-century America and went on to lay the groundwork for pragmatism, an approach to philosophy with wind in its sails to this day. To have James defending the idea of telepathy is akin to having Stephen Hawking throwing his reputation behind intelligent design or sightings of UFOs.

The extraordinary fact about James’s support of psychical research is that, unlike Twain, he never experienced anything like a telepathic experience himself. He took the same attitude toward religious experience more broadly, offering philosophical defenses of religious belief while confessing that he had had no personal experience of the divine. At best he admitted to glimpses and hunches.

James’s religious optimism was aspirational rather than experiential. And yet in works such as “The Will to Believe” and The Varieties of Religious Experience, James tirelessly defended religion against the dismissals of science and academia. His former student Walter Lippmann saw in this something fundamentally American: “He showed that this democratic attitude of mind is every bit as fruitful as the aristocratic determination to ignore new and strange-looking ideas. James was a democrat. He gave all men and all creeds, any idea, any theory, any superstition, a respectful hearing.”

In addition, James saw psychical research as an extension of honest science. His “radical empiricism” aimed to include all types of human experiences, including those that couldn’t be reproduced in a lab. To listen to stories of spiritual phenomena and to observe mediums in action were part of the discipline of induction. And in a field in which emotions could run high and were easily manipulated, James remained a fairly cool observer, cautioning fellow researchers against hasty conclusions and admitting that 25 years of involvement in research had left him “theoretically no further than I was at the beginning.”

However open-minded he remained, James was sober about the actual payoff of psychic communication. If in fact the dead can communicate with the living—which remained an open question to James—it was disappointing to note the vagueness of the consolations and the triviality of the messages. James observed: “What real spirit, at last able to revisit his wife on this earth, but would find something better to say than that she had changed the place of his photograph?” Indeed, what are we to glean from Alfred Russel Wallace’s account of a bouquet of flowers covered in dew suddenly appearing on a parlor table?

It’s not that it’s not interesting or uncanny for a medium to know things about a man’s extended family or his past, it’s just that such trivia doesn’t compel any meaningful response. It seems too much like card-reading; it has the whiff of entertainment. Woody Allen’s quip, in which he asks God for a sign, any sign, such as a large deposit in a Swiss bank account, comes to mind. Give us something we can use. Occasionally the mediums offered broad-stroke consolations, but mostly their consolations strike us as curiosities. And so while science and religion continue to wage the turf battles begun in the 19th century, psychics, who had been prominent in the late-Victorian world of Ghost Hunters, are culturally marginalized. They are viewed as novelties rather than prophets, and their ancestors seem like emblems of a culture in transition rather than discoverers of the profoundly new. Séances are as dated and quaint as streetcars.

Some tribute, however, must be paid to James’s favorite medium, Leonora Piper, a quiet heroine in Blum’s account. Piper had her first experience of psychic communication at the age of eight, when she “stammered” a message to her mother from an Aunt Sara, who, miles away and unknown to the Pipers, had just died. When she was a young woman, Leonora was sought by many. She would relax into a trance state and, through altered voices and temperaments, would tell people things she could not know through ordinary means and would sometimes offer messages of comfort from dead loved ones. Piper spent a week at James’s country home, and James remarked that if anyone was to be his white crow—the true medium among flocks of charlatans—it would be she. And yet he was never quite convinced. His hunch was that while something was going on in her trance states, it couldn’t be interpreted or explained as supernatural communication. True to form, James was content with this indeterminacy.

Other researchers were less kind to Piper. The extraordinary measures male scientists took to restrain and trip up female mediums—and they were almost all female—form a sad substory to the one Blum tells. To test Piper to see if she was faking her trance state, for example, Richard Hodgson “put ammonia-soaked cloth under her nose, dumped spoonfuls of salt, perfume, and laundry detergent into her mouth, pinched her until she bruised, all without provoking a flinch.” The skeptical professor G. Stanley Hall tried to disturb her trance by pouring spirit of camphor into her mouth, a gesture of scientific inquiry that left Piper’s lips and tongue blistered. Blum’s narrative is important and fascinating, but the evidences of gender struggle deserve more commentary than she offers.

Ghost Hunters explores the strange Victorian netherworld between rapidly advancing science and rapidly adjusting religion. In terms of cultural authority, science clearly won the day. But the work that William James did to defend unorthodox experience a hundred years ago describes intellectual space for religion to inhabit in any scientific age. There is a trade-off, though: the space James defended is a realm of ambivalence, idiosyncrasy and inaccessibility, and religious believers can’t easily embrace the idea that their deepest sense about the world is more like Twain’s uncanny hunch than like an apprehension of the laws of physics.