Do you really know? Why do people say the soul weighs 21 grams ?
Jan 11, 2026
Explore the bizarre claim that the soul weighs 21 grams, stemming from Duncan MacDougall's early 20th-century experiments. Discover how he weighed dying patients and thought the weight loss indicated the soul's release. Learn about scientific criticisms and alternative explanations, including physiological factors like temperature. MacDougall’s controversial experiments with dogs add to the intrigue. Finally, delve into how this quirky idea permeated popular culture, culminating in a film that brought it to the masses.
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Origin Of The 21 Grams Claim
- Duncan McDougall measured dying patients and concluded they lost about 21 grams at death.
- He inferred this loss was the soul leaving the body despite no scientific basis for a soul's existence.
McDougall's Patient And Dog Experiments
- McDougall weighed six dying patients and reported one showed a ~21 gram loss at death.
- He later repeated experiments on about 15 dogs and reportedly found no weight change in them.
Physiological Explanations Undercut The Claim
- Critics argued physiological changes at death can explain small weight shifts, like sweating due to temperature changes.
- Augustus P. Clarke specifically attributed perceived weight loss to postmortem cooling and skin sweating.