How much does the soul weigh?

A person's soul is said to weigh 21 grams. Is there any basis for this?

A strong idea, the foundation of many religions, and a very consoling notion in the face of loss is that of an eternal soul.

Perhaps this is the reason some people have become unhappy with leaving questions of the soul to religion and instead turned to science in an effort to establish the existence of the soul. You've probably heard the findings of one of these pretty peculiar investigations if you've ever heard that the soul weighs 21 grams or if you've watched the 2003 movie "21 Grams," which makes reference to this idea.

What weight does the soul actually have? The bad news is that nobody can definitively answer that. Scientists are unable to measure or establish the existence of the soul. But it's worth sticking around for the odd tale of one doctor's attempt to accomplish precisely that.

Beginning in the Boston neighborhood of Dorchester around the turn of the 20th century. Duncan MacDougall, a renowned doctor, had an idea that bugged him: if people had souls, those souls had to occupy space. Additionally, since souls occupy space, they must weigh something, right?

The soul's weight

MacDougall reasoned that there was only one way to learn the answer. It seems more logical to me to think that the substance considered in our hypothesis must be some form of gravitative matter, and therefore capable of being detected at death by weighing a human being in the act of death, he wrote in the scientific paper he would eventually publish(opens in new tab) about this endeavor in 1907.

MacDougall collaborated with Dorchester's Consumptives' Home, a nonprofit medical facility for people with terminal TB, which was then an incurable disease. A big scale that MacDougall constructed can accommodate a cot and a TB sufferer who is near death. For this experiment, MacDougall chose tuberculosis as a suitable condition since patients passed away from it in "extreme fatigue" and without any movement that would disturb his scale.

On April 10, 1901, a man who was MacDougall's first patient passed away after experiencing a sharp reduction in weight of 0.75 ounce (21.2 grams). The mythology began to take shape right then. The fact that MacDougall's subsequent patient dropped 0.5 ounce (14 grams) 15 minutes after passing out or that his third instance had an illogical two-step loss of 0.5 ounce and then 1 ounce (28.3 g) a minute later didn't really matter either.

Case 4, involving a woman who was dying of diabetes, was rejected by MacDougall because the scale had not been properly calibrated, in part because of "a good deal of interference by people opposed to our work." This decision raises some questions, which MacDougall did not appear particularly eager to address in his write-up. Case 5 dropped 0.375 ounce (10.6 grams), however the scale afterwards developed problems, so those figures are also in doubt. Because the patient passed away while MacDougall was still calibrating his scale, Case 6 was dismissed.

The studies were subsequently carried out again on 15 dogs, and MacDougall discovered no weight loss, concluding, in his opinion, that not all canines get to paradise.

In 1907, MacDougall published his findings in the American Medicine and Journal of the American Society for Psychical Research journals. He received an article in The New York Times as well (opens in new tab).

Intractable issues

Even at the time, MacDougall's study's results were inconsistent and its tiny sample size seriously called into question the idea that he examined the soul. To MacDougall's credit, he acknowledged that more measurements were required to establish the soul's mass. That hasn't happened due to a combination of ethical concerns and the trials' peculiar nature. According to Mary Roach's book "Spook: Science Tackles the Afterlife," a rancher in Oregon did make an attempt to repeat the soul-weighing experiment with a dozen sheep in the early 2000s (W. W. Norton & Co., 2005). The majority gained between 1 and 7 ounces (between 30 and 200 grams), however the weight increases were short-lived, with the sheep quickly reverting to their initial weights.

Dr. Gerry Nahum, a chemical engineer and medical professional who was attending the Duke University School of Medicine at the time, was also mentioned by Roach as having developed the theory that the soul, or at the very least, consciousness, must be connected to information, which is equivalent to a certain amount of energy. This energy might, in theory, be weighed with sensitive enough electromagnetic equipment because the equation E = mc 2 states that energy equals mass times the speed of light squared (thanks, Einstein). Nahum had not received money as of 2007(opens in new tab) for tests that would have demonstrated if he was correct. His current employer is Bayer Pharmaceuticals. (Roach said that Nahum had no plans to do a MacDougall and conduct his experiments on live subjects. He was thinking of leeches as topics instead.)

The truth is that neither the existence of the soul nor its weight have been remotely defined by science. The area of religion will probably be left to address this issue.