In the late 19th and early 20th centuries, leading scientists around the world believed that paranormal activity might be detected and demonstrated by scientific methods. The history of their attempts tells us something important about the limits and specificity of scientific expertise.
The Society for Psychical Research was founded in the U.K. in 1882 to investigate possible paranormal activity, including mesmerism, thought transference, apparitions and even haunted houses. Prominent members included economist Henry Sidgwick, physicist Oliver Lodge (a pioneer in the study of electromagnetism), and writer Arthur Conan Doyle. These men sought to study the subject in a scientific manner, “without prejudice or prepossession of any kind.” Other well-known scientists who attended séances included Harvard University psychologist and philosopher William James (one of the founders of a philosophical school known as pragmatism) and British biologist Alfred Russel Wallace (who, along with Charles Darwin, developed the theory of evolution by natural selection).
Mainstream media reported on these efforts, often uncritically. “Soul Has Weight, Physician Thinks,” declared a New York Times headline on March 11, 1907. With four medical colleagues as witnesses, “reputable physician” Duncan MacDougall of Massachusetts had placed the body of a dying man on a specially designed bed, with built-in scales, next to an empty but otherwise identical bed. At the moment of the man’s death, the scales reportedly shifted, indicating a weight loss on his side of approximately one ounce. Five other cases showed losses between an ounce and half an ounce. In the case of one large, “phlegmatic” man, the weight loss was delayed a minute; MacDougall concluded that the deceased’s sluggish nature led his soul to depart without alacrity. (Wikipedia suggests this experiment is the source of the popular notion that the human soul weighs 21 grams.)
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The Times similarly reported the work of Charles Henry, a mathematics professor at the Sorbonne in France. “Soul Can Be Measured, Mathematician Holds,” a headline announced on September 20, 1925. The evidence here consisted of radiating “biological vibration,” which occurred when death disrupted life’s delicate equilibrium. This observation marked “the first time science has ever admitted that tangible proof of the soul’s existence may be found,” the article asserted, insisting that the professor was not a “psychic or a dreamer” but a scientist who had harnessed “all the information available about colored auras and recollections of previous existences that so far have been almost exclusively exploited by cranks.”
These accounts remind us that the views of a scientist are not necessarily equivalent to “science.” MacDougall and Henry might have believed they had proved the soul’s existence, but most of their contemporaries did not. One obvious problem was that these experiments assumed the existence of the thing they were trying to prove—essentially a circular argument.
The history of psychical research also shows why we should take novel scientific claims with a grain of salt, especially those that would fulfill one of our dearest wishes, such as communicating with lost loved ones or enjoying eternal life. What seems plausible today—even at Harvard and the Sorbonne—may appear preposterous down the road.
Perhaps the most important lesson, though—especially in our current environment saturated with misinformation and disinformation—concerns the specificity of scientific expertise: scientists are specialists, and their training rarely prepares them to evaluate claims beyond their particular areas of focus.
What expertise, exactly, would be needed to evaluate claims of the supernatural or paranormal? Another tale from the annals of psychic inquiry helps to answer that question. It is the story of Boston medium Mina Crandon, popularly known as “Margery.”
In 1922 Scientific American announced the establishment of a prize committee to investigate psychic claims, promising $5,000 to anyone who could demonstrate the reality of paranormal or supernatural activity. Margery had been put forward as a candidate. Her evaluation committee included Harvard psychologist and member of the Royal Society William McDougall; Massachusetts Institute of Technology physicist Daniel F. Comstock (who later helped to develop the Technicolor process for making color movies); and world-renowned magician and escape artist Harry Houdini. Although the historical facts are somewhat disputed, it seems that the committee was leaning toward awarding Margery the prize until Houdini identified her techniques as the tricks they were. It was a magician—not a physicist or a mathematician—who had the expertise to recognize the supposed medium’s sleight of hand.
Nowadays all kinds of people make scientific claims, often with little or no expertise in the matter at hand. Some are scientists driving outside their lane. American physicist and inventor William Shockley, who shared the 1956 Nobel Prize in Physics for creating the transistor, used his stature to promote racism and eugenics.
Physicist John F. Clauser, a 2022 Nobel Laureate who was honored for his contributions to quantum information science, is a self-declared climate change “denier” who has been taking to podiums around the world to argue against the scientific consensus that the planet is undergoing dangerous warming. Various celebrities have falsely claimed that vaccines cause autism, and politician Robert F. Kennedy, Jr., is spreading misinformation about vaccines as part of a presidential campaign.
So the next time you are wondering whom to trust about a scientific matter, ask yourself this: Who has the necessary expertise to assess this situation? Put simply: Who is the Houdini in this case?
This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.