21 grams experiment

The 21 grams experiment was an unorthodox test conducted by Massachusetts physician Dr. Duncan MacDougall, with results published in 1907. In this test, MacDougall attempted to study the weight of dying human patients to determine whether any perceptible changes would occur that could help to prove the existence of the soul. One of the patients exhibited weight loss that MacDougall measured at about 21 grams, which he tentatively suggested might be the proof he had sought. Despite a brief furor about these experiments and findings, by modern times, MacDougall’s work has been roundly discredited on a variety of levels.

Background

One of the core concepts of many religious systems is the idea that human beings have a soul. While people have contemplated and formed beliefs about the soul for thousands of years, the exact nature of the soul and its possible existence remains highly uncertain. For most, the term soul refers to an unseen, spiritual essence that inhabits the body during life. The soul may be seen to cause life, or to be the animating force of life itself. It may also be considered a unique entity that encapsulates an individual’s truest essence and identity.

Ideas of the soul have also become entwined in the concepts of life, death, and possible life after death. Many people believe that, upon an individual’s death, the soul departs the body, likely to face judgment for behaviors during life or to return to some otherworldly place or state, such as the Heaven of Christianity. Many believe that, based on what occurs to the soul after death, the soul might be transferred into a new body, thus completing a cycle of reincarnation and proving that humans may be reborn indefinitely in new forms.

For these reasons, concepts of the soul have been of extreme importance to countless religious groups and spiritual-minded philosophers through the millennia. The immaterial nature of the supposed soul, however, has largely rendered it incapable of being studied scientifically, leaving it as a matter of faith. However, some scientists have attempted to research or even quantify the soul in various ways, hoping that their discoveries could answer some of humanity’s oldest and most pressing questions about the origins of life, the nature of death, and the existence of supernatural forces.

Overview

Scientists have long pondered the mysteries of death. Over time, their findings have shown that the human body, as well as the bodies of other animals, exhibit distinct and sudden changes at the moment of death. Among these changes are relaxation of the muscles, including the sphincter muscles, leading to expulsion of waste. The halting of blood flow causes the body temperature to sharply rise, and cell death triggers chemical changes that eventually begin the process of decomposition.

Despite these well-documented changes, no scientist has been able to soundly identify any phenomenon relating to death that would confirm the existence of the soul. The most notable experiment to test this question occurred around 1907, when Massachusetts physician Dr. Duncan MacDougall conducted a strange and unique test that came to be known as the “21 grams experiment.” This experiment was based on the idea that the soul might have physical mass, meaning that its departure from the body upon death would lead to a perceptible weight loss.

In preparation for this test, MacDougall built a bed in his office that rested upon platform beam scales, which he calculated could read weight fluctuations down to two-tenths of one ounce. With the platform set up, MacDougall brought in six people in the last stages of life, including some suffering from tuberculosis and acute diabetes. He carefully watched and monitored them in their final hours, including recording their weight.

MacDougall was aware of normal physiological reasons for weight loss during death, as well as during regular activity, including respiration and sweat evaporation. However, he believed that he had taken those everyday factors properly into account. He also endeavored to account for the weight of any air loss caused by a final exhalation, though in his tests he found such exhalations to have no measurable weight.

One of the six patients MacDougall observed experienced a small but noticeable weight loss at the moment of death that MacDougall could not dismiss as having any normal physiological cause. The unaccounted-for weight was three-fourths of an ounce, or about 12 grams. To MacDougall, this loss defied any regular explanation and led him to postulate that the lost weight might represent the departure of the patient’s soul at the time of death.

The other patients experienced other strange fluctuations in weight near, during, and after their deaths. One patient lost but then regained weight, and two lost weight but then gained more weight a few minutes afterward. MacDougall did not explore these occurrences in detail, however, but rather focused on the 21-gram loss.

Before publicizing his results, MacDougall conducted other tests, notably with fifteen dogs. He explained that the ideal canine candidates would already have a life-threatening illness but admitted that he could not find any, leading modern researchers to suspect that he poisoned otherwise healthy dogs for the experiment. Regardless, MacDougall detected no unexplainable changes to the animals’ weights at the time of their deaths. Rather than considering that damning evidence for the existence of the soul, MacDougall suggested that it made sense and indeed served as proof that dogs, unlike humans, do not have a soul.

MacDougall’s findings and assertions were published widely in 1907 in the medical journal American Medicine as well as the New York Times. MacDougall stressed that he did not consider his work to have definitively proven that the soul exists or departs the body upon death and that other scientists would have to perform other tests to contribute to the study.

Regardless, his findings and their possible implications created a stir of activity on several levels. Many religious-minded people were inclined to accept them. Many in the medical community, however, took strong opposition to his findings and, in particular, the nature of his work. Critics pointed out that his results were inconsistent, his techniques were clumsy, and his sample size of one patient exhibiting a strange phenomenon was insufficient to produce meaningful data. Some physicians actively debated MacDougall on other points, such as that humans and dogs have physical differences that invalidate their comparison.

Debates over MacDougall’s work continued for months, though neither MacDougall nor other scientists made any serious attempts to replicate the experiment. MacDougall did not lose interest in the supernatural, however, and within four years had moved on to experimenting with the possibility of photographing souls using X-ray technology. By the twenty-first century, his work has been almost universally discredited and the “21 grams experiment” has been downgraded to a pseudoscientific novelty.

Bibliography

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