Duncan MacDougall (doctor)
October 15, 1920(aged 54)
|Residence||Haverhill, Massachusetts, USA|
|Known for||attempting to determine the mass of a soul|
Dr. Duncan "Om" MacDougall (c. 1866 – October 15, 1920) was an early 20th-century physician in Haverhill, Massachusetts who sought to measure the mass lost by a human when the soul departed the body at death. MacDougall attempted to measure the mass change of six patients at the moment of death. His first subject, the results from which MacDougall felt were most accurate, lost "three-fourths of an ounce", which has since been popularized as "21 grams". Of the four successful measurements he obtained an average weight loss at the moment of death of 15 grams. The total average unaccounted for weight loss in these four subjects was found to be approximately 29 grams.
Ideas about the 'soul'
In 1901, MacDougall weighed six patients while they were in the process of dying from tuberculosis in an old age home. It was relatively easy to determine when death was only a few hours away, and at this point the entire bed was placed on an industrial sized scale which was reported to be sensitive to "two-tenths of an ounce". He took his results (a varying amount of unaccounted for mass loss in four of the six cases) to support his hypothesis that the 'soul' had mass, and when the 'soul' departed the body, so did this mass. The determination of the 'soul' weighing 21 grams was based on the loss of mass in the first subject at the moment of death.
MacDougall later measured fifteen dogs in similar circumstances and reported the results as "uniformly negative," with no perceived change in mass. He took these results as confirmation that the 'soul' had weight, and that dogs did not have 'souls'. MacDougall's complaints about not being able to find dogs dying of the natural causes that would have been ideal led one author to conjecture that he was in fact sacrificing the experimental animals, as is standard practice in scientific experiments. On March 10, 1907, before MacDougall was able to publish the results of his experiments, New York Times broke the story in an article titled "Soul has Weight, Physician Thinks". MacDougall's results were published in April of the same year in the Journal of the American Society for Psychical Research and the medical journal American Medicine.
Later researchers showed that MacDougall's experimental results were flawed, due to the limitations of the available equipment at the time, a lack of sufficient control over the experimental conditions, and the small sample size.
Science writer Karl Kruszelnicki has noted that out of MacDougall's six patients only one had lost weight at the moment of death. Two of the patients were excluded from the results due to "technical difficulties", a patient lost weight but then put the weight back on and two of the other patients registered a loss of weight at death but a few minutes later lost even more weight. MacDougall did not use the six results just the one that supported his hypothesis. According to Kruszelnicki this was a case of selective reporting as MacDougall had ignored five of the results.
The physicist Robert L. Park has written MacDougall's experiments "are not regarded today as having any scientific merit" and the psychologist Bruce Hood wrote that "because the weight loss was not reliable or replicable, his findings were unscientific."
In popular culture
- MacDougall's experiments are mentioned and reenacted in the 1978 film Beyond and Back.
- A fictional American scientist named "Mr. MacDougall" appears as a character in Gail Carriger's steampunk adventure novel Soulless, as an expert in the weight and measurement of souls.
- MacDougall and his experiment were a subject in a 2011 episode of Science Channel's Dark Matters: Twisted But True.
- The idea from these experiments show up in the Dan Brown novel The Lost Symbol.
- 21 Grams is a 2003 American drama film which references the notion that the human soul has mass, more specifically that it weighs twenty-one grams.
- MacDougall's experiment was mentioned in the comic series "The Unknown". Two characters are presumed to have tried to replicate the experiment with much more high-tech equipment.
- Mikkelson, Barbara; Mikkelson, David P. (October 27, 2003). "Soul Man". Snopes. Retrieved February 17, 2007.
- Kruszelnicki, Karl. (2006). Great Mythconceptions: The Science Behind the Myths. Andrews McMeel Publishing. pp. 200-202. ISBN 978-0-7407-5364-0
- Park, Robert L. (2009). Superstition: Belief in the Age of Science. Princeton University Press. p. 90. ISBN 978-0-691-13355-3
- Hood, Bruce. (2009). Supersense: From Superstition to Religion - The Brain Science of Belief. Constable. p. 165. ISBN 978-1-84901-030-6
- MacDougall, Duncan. (1907). The Soul: Hypothesis Concerning Soul Substance Together with Experimental Evidence of the Existence of Such Substance. American Medicine. New Series 2: 240-243.
- Summary of MacDougall's research at Snopes.com
- Full text Dr. Duncan MacDougall “Hypothesis Concerning Soul Substance, Together with Experimental Evidence of the Existence of Such Substance” , Journal of the American Society for Psychical Research, May 1907
- Original article, Full Text, as above, another source, easier to read formatting.
- NYT archives of newspaper article from March 11th 1907
- Related paper by Lewiss E. Hollander, Jr. showing transient weight increase at time of death for sheep.
- Weight fluctuations of memories upon erasure or writing, research website at the Department of Electrical and Computer Engineering, Texas A&M University