Duncan MacDougall (doctor)
October 15, 1920(aged 54)
|Residence||Haverhill, Massachusetts, USA|
|Known for||attempting to weigh the soul upon death|
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 body when the soul departed the body upon death.
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 apparently sensitive to the gram. He took his results (a varying amount of perceived mass loss in most 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 average loss of mass in the six patients within moments after death. Experiments on mice and other animals took place. Most notably the weighing upon death of sheep seemed to create mass for a few minutes which later disappeared. The hypothesis was made that a soul portal formed upon death which then whisked the soul away.
MacDougall also 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 poisoning dogs to conduct these experiments. In March 1907, accounts of MacDougall's experiments were published in the Journal of the American Society for Psychical Research and the medical journal American Medicine, while the news was spread to the general public by New York Times.
MacDougall's results are generally regarded as false, due to the flawed methodology used in the tests. All attempts to reproduce the results with better methodologies and equipment have failed. Author Robert L. Park also raises objections to MacDougall's findings in his "Superstition: Belief in the Age of Science." 
MacDougall's results are also brought into question due to the extreme variability in what few human subjects he had. Of the six people used, two were discounted for technical reasons, two lost weight initially which then continued to fall, and one lost weight which was later regained. Only one of the six had a sustained, non-changing loss in weight of approximately 21 grams.
Nonetheless, MacDougall's finding that presumably the human soul weighed 21 grams has become a meme in the public consciousness, mostly due to its claiming the titular thesis in the 2003 film 21 Grams.
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.
- Mikkelson, Barbara; Mikkelson, David P. (October 27, 2003). "Soul Man". Snopes. Retrieved February 17, 2007. "MacDougall's ... methodology ... was suspect, [his] sample size far too small, and [his] ability to measure changes in weight imprecise. For this reason, credence should not be given to the idea his experiments proved something, let alone that they measured the weight of the soul ... His postulations on this topic are a curiosity, but nothing more."
- Robert L. Park. Superstition: Belief in the Age of Science; Princeton University Press; 2009; page 90
- 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