Crookes in an 1876 portrait from Popular Science

William Crookes, born today in 1832, was a deft scientist—in Britain, he identified the first sample of helium, discovered thallium, invented a radiometer, and developed a vacuum tube to study cathode rays. But he was also a total naïf.

Swayed by spiritualism and the faddish pseudoscience of the day, Crookes regularly attended séances and joined both the Theosophical Society and the Ghost Club—still extant, should you care to sign up. The Hermetic Order of the Golden Dawn, perhaps the best-named misguided occultist group in the history of misguided occultist groups, inducted him in 1890.

What drew someone of Crookes’s occupation into such fraudulent circles? Some say it was grief—Crookes’s brother had died from yellow fever at only twenty-one, and the scientist presumably yearned to speak with him again. Whatever the case, Crookes’s research papers on the paranormal, and thus whole years of his life, are swathed in a kind of dramatic irony. He was one of the few men in his profession who bought into these shaky accounts of the otherworldly. His writing on supernatural phenomena, so outwardly rigorous, shines with melancholy when you realize how deeply he wanted to believe. It’s bad science on good faith.

His 1974 report, “Notes of an Enquiry into the Phenomena called Spiritual during the Years 1870–1873,” is available in full online. The title alone carries all the official, upright skepticism of the Royal Society—from which Crookes was nearly ejected, when he started writing on this subject in earnest—and the scientific method. For all its seeming caution, its every page is grossly erroneous. Crookes divides the “phenomena” into thirteen increasingly vague classes, e.g., “The Appearance of Hands, either Self-Luminous or Visible by Ordinary Light”; “Special Instances Which Seem to Point to the Agency of an Exterior Intelligence”; “Miscellaneous Occurrences of a Complex Character.” He swears up and down that he’s scrupulous and objective, but he seldom mentions the specifics of his methodology; instead, he writes with evident rapture about the seemingly impossible (read: impossible) marvels he’s seen. And heard, for that matter:

I have heard delicate ticks, as with the point of a pin; a cascade of sharp sounds as from an induction coil in full work; detonations in the air; sharp metallic taps; a crackling like that heard when a fractional machine is at work; sounds like scratching; the twittering of a bird, etc. … In the case of Miss Fox it seems only necessary for her to place her hand on any substance for loud thuds to be heard in it, like a triple pulsation, sometimes loud enough to be heard several rooms off … I have tested them in every way that I could devise, until there has been no escape from the conviction that they were true objective occurrences not produced by trickery or mechanical means.

Elsewhere, he writes, “Under the strictest test conditions, I have more than once had a solid, self-luminous, crystalline body placed in my hand by a hand which did not belong to any person in the room.” And he introduces a section called “The Levitation of Human Beings” like so: “This has occurred in my presence on four occasions in darkness.”

All of this says disquieting things about our capacity to be deceived. When you read Crookes’s paper in light of his brother’s early death, it’s hard not to be affected by lines like this: “To the touch, the hand sometimes appears icy cold and dead, at other times, warm and life-like, grasping my own with the firm pressure of an old friend.”

The science historian Sherrie Lynne Lyons wrote, “Here was a man with a flawless scientific reputation, who discovered a new element, but could not detect a real live maiden who was masquerading as a ghost.” Harry Houdini put it more bluntly: “There is not the slightest doubt in my mind that this brainy man was hoodwinked.”