MacDougall stated his experiment would have to be repeated many times before any conclusion could be obtained. The experiment is widely regarded as flawed and unscientific due to the small sample size, the methods used, as well as the fact only one of the six subjects met the hypothesis.[1] The case has been cited as an example of selective reporting. Despite its rejection within the scientific community, MacDougall's experiment popularized the concept that the soul has weight, and specifically that it weighs 21 grams.
In 1901, Duncan MacDougall, a physician from Haverhill, Massachusetts, who wished to scientifically determine if a soul had weight, identified six patients in nursing homes whose deaths were imminent. Four were suffering from tuberculosis, one from diabetes, and one from unspecified causes. MacDougall specifically chose people who were suffering from conditions that caused physical exhaustion, as he needed the patients to remain still when they died to measure them accurately. When the patients looked like they were close to death, their entire bed was placed on an industrial sized scale that was sensitive within two tenths of an ounce (5.6 grams).[1][2][3] On the belief that humans have souls and that animals do not, MacDougall later measured the changes in weight from fifteen dogs after death. MacDougall said he wished to use dogs that were sick or dying for his experiment, though was unable to find any. It is therefore presumed he poisoned healthy dogs.[3][4][5]
One of the patients 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. One of the patients lost "three-fourths of an ounce" (21.3 grams) in weight, coinciding with the time of death. MacDougall disregarded the results of another patient on the grounds the scales were "not finely adjusted", and discounted the results of another as the patient died while the equipment was still being calibrated. MacDougall said that none of the dogs lost any weight after death.[1][4]
An article by Snopes in 2013 said the experiment was flawed because the methods used were suspect, the sample size was much too small, and the capability to measure weight changes too imprecise, concluding: "credence should not be given to the idea his experiments proved something, let alone that they measured the weight of the soul as 21 grams."[4] The fact that MacDougall likely poisoned and killed fifteen healthy dogs in an attempt to support his research has also been a source of criticism.[3][4]
In December 2001, physicist Lewis E. Hollander Jr. published an article in Journal of Scientific Exploration where he exhibited the results of a similar experiment. He tested the weight of one ram, seven ewes, three lambs and one goat at the moment of death, seeking to explore upon MacDougall's purported findings. His experiment showed that seven of the adult sheep varied their weight upon dying, though not losing it, but rather gaining an amount of 18 to 780 grams, which was lost again over time until returning to their initial weight.[10] In 2009, Hollander Jr.'s experiment was subjected to critical review by Masayoshi Ishida in the same journal. Ishida found Hollander's statement of a transient gain of weight was "not an appropriate expression of the experimental result", though he admitted "the cause of the force event remains to be explained". He also warned about possible malfunctions of the weighing platform in two of the cases.[11]
Despite its rejection as scientific fact, MacDougall's experiment popularized the idea that the soul has weight, and specifically that it weighs 21 grams.[1][5] The title of the film 21 Grams references the experiment.[2][4][5]
The concept of a soul weighing 21 grams is mentioned in numerous media, including a 2013 issue of the manga Gantz,[13] a 2013 podcast of Welcome to Night Vale,[14] the 2015 film The Empire of Corpses[15] a 2021 episode of Ted Lasso,[16] and a 2023 issue of the manga One Piece.[17] Songs entitled "21 Grams" which reference the weight of a soul have been released by Niykee Heaton (2015),[18] Fedez (2015), August Burns Red (2015) and Thundamentals (2017). Travis Scott references the concept in the song "No Bystanders", released in 2018. MacDougall and his experiments are explicitly mentioned in the 1978 documentary film Beyond and Back,[19] and episode five of the first season of Dark Matters: Twisted But True.[20] A fictional American scientist named "Mr. MacDougall" appears in Gail Carriger's 2009 novel Soulless, as an expert in the weight and measurement of souls.[21]
The trailer for the 2003 movie, 21 Grams, starts off with a sentence that is both authoritative and inexact: "They say that we all lose 21 grams at the exact moment of death". It's a short and sweet attention-grabber - but the science behind that sentence adds up to zero.
People have believed that the "soul" has a definite physical presence for hundreds, and possibly thousands, of years. But it was only as recently as 1907, that a certain Dr. Duncan MacDougall of Haverhill in Massachusetts actually tried to weigh this soul. In his office, he had a special bed "arranged on a light framework built upon very delicately balanced platform beam scales" that he claimed were accurate to two-tenths of an ounce (around 5.6 grams). Knowing that a dying person might thrash around and upset such delicate scales, he decided to "select a patient dying with a disease that produces great exhaustion, the death occurring with little or no muscular movement, because in such a case, the beam could be kept more perfectly at balance and any loss occurring readily noted".
Second, he got "good" results (ie, the patient irreversibly lost weight at the moment of death) from just one of the six patients, not all six! Two of the results had to be excluded because of "technical difficulties". One patient's death did show a drop in weight of about three-eighths of an ounce - but this later reversed itself! Two of the other patients registered an immediate loss of weight at the moment of death, but then their weight dropped again a few minutes later. (Does this mean that they died twice!?) Only one of the six patients showed a sudden and non-reversible loss of weight of three-fourths of an ounce (21 grams).
For the season opener, production designer Ray Kluga transformed an airport hangar in New York into a space for a group of scientists to experiment on dead bodies. The idea was to measure the weight of a soul, a question that goes back to the early 20th century when scientist Duncan MacDougall determined the weight lost after death was 21 grams.
He mentioned that the weight of a human soul was approximately 21 grams. At the very least, this was the theory put forth by a scholar from West Blue. What makes this measurement important, however, is that it's a reference to a real-world experiment based on measuring human souls.
The 21 grams experiment was conducted by Duncan MacDougall at the beginning of the 20th century. The physician hypothesized that the human soul had a weight to it and conducted an experiment to figure out just what that weight was. He took six patients at death's door and weighed each of them at the moment of death. One such patient notably lost three-quarters of an ounce, which comes out to 21.3 grams.
Unfortunately for MacDougall, the scientific community didn't agree with his assessment. They pointed out several flaws with his limited sample size and unreliable methods. He also based his conclusion on one of six patients, and even that patient's weight loss could arguably be explained scientifically. In the end, the 21 grams experiment became a prime example of selective reporting.
Despite the incredulity surrounding MacDougall's experiment, it gained popularity due to its concept. The idea of a soul having weight had a sort of romanticism to it, which is probably why MacDougal's proposed weight of 21 grams has been used so often in popular culture. It's been featured in all sorts of songs, novels, and TV shows. In the world of anime, the soul weighing 21 grams has also been referenced in Gantz and Empire of Corpses. Since most of these are works of fiction, fantasy, and sci-fi, it's reasonable to assume that there is a soul and it does weigh 21 grams in their stories.
In all likelihood, however, the true weight of the soul will probably end up being irrelevant. Vegapunk only brought up this experiment as a lead-in to his discussion of weighing memory. That said, if the topic of a soul's weight ever does somehow come back, it will likely be confirmed to weigh 21 grams for lack of a better answer.
Following the experiment and consulting with the other attending physicians, the average weight loss of each person appeared to be  of an ounce. Dr. MacDougall concluded a human soul weighed 21 grams.
The human soul is said to weigh 21 grams. But what is the soul, and what makes us human? What do friendship, relationship, partnership entail? How and, most importantly, who defines us and our (gender) identity, our way of loving and living? Is it society? Or rather we ourselves? In her book, the photographer Celine Yasemin addresses these fundamental questions. She has turned her lens on friends and fleeting acquaintances, people from various cultural and social backgrounds who do not identify with the norm, who live a self-determined life with different experiences, preferences, and approaches to life, who comply neither with traditional roles nor relationship models.
38c6e68cf9