Dr. Duncan MacDougall - The Man Who Tried to Weigh the Soul

Dr. Duncan MacDougall, a physician, born in Glasgow in 1866, moved to Haverhill, Massachusetts, in the United States when he was about 20 years old. He attended the Boston University School of Medicine and received a medical degree.

After graduation, he returned to Haverhill, where he began his medical practice. He married Mary Storer, and in 1985 they had a son, John.

Dr. MacDougall assumed that the souls had physical weight and tried to measure the weight lost by the human when the soul left the body. MacDougall attempted to measure the mass change of six patients at the time of death, but only four ended up being useful, as two of them had to be discounted due to some technical issues with scale, so the results were based on four patients – only one of whom showed weight loss which is three-fourths of an ounce (21.3 grams).

In 1907, Dr. McDougall described his experiment by putting the beds of dying patients on the sensitive weighing scale. Then, when the patients looked like they were close to death, their entire bed was shifted to an industrial scale sensitive within two-tenths of an ounce (5.6 grams). Believe it or not, he was trying to weigh down the human soul! 

Dr. McDougall was so keen on this experiment that he recorded the exact time of each patient's death and his or her total time on the bed, as well as any changes in weight that occurred around the moment of expiration or during urine and fecal eliminations.

As per the belief that humans have souls and that animals do not, MacDougall later trying the same experiment with 15 dogs, which recorded no change in weight at the time of their deaths; he was even more encouraged, this fitted perfectly with the popular belief that there was no soul for a dog and would record no weight loss at the time of death.

Dr. Duncan MacDougall published his experiments in the April 1907 edition of "American Medicine" and the "Journal of the American Society for Psychical Research." The paper was titled "Hypothesis Concerning Soul Substance Together with Experimental Evidence of The Existence of Such Substance."

The experiment is widely considered flawed and non-scientific due to the small sample size, the methods Dr. MacDougall's used, and the fact that only one of the six subjects met the hypothesis.

Also, experts criticized the accuracy of the equipment used by MacDougall, as well as the fact that only one patient had marked results.

Dr. Augustus P. Clarke, an American physician, criticized the experiment as having caused a sudden rise in body temperature at the time of death, as the lungs stop working. As a result, their cooling effect on the bloodstream goes away, resulting in sweating and loss of moisture by evaporation through the skin surface that could easily account for weight loss, and he also pointed out that as dogs do not have sweat glands, they would not lose weight after death. 

Despite the rejection within the scientific community, Dr. MacDougall's experiment popularized the notion that the soul has weight and, specifically, that it weighs 21 grams.