I simply believe that some part of the human Self or Soul is not subject to the laws of space and time.

Carl Jung

In 1901 a man called Dr Duncan MacDougall embarked on an experiment in Dorchester, Massachusetts. His aim was to prove that the human soul had mass. And if it did, then it was therefore measurable.


With their consent, MacDougall conducted this experiment on six terminally ill patients, who were placed on specially-made Fairbanks scales just prior to their deaths. His intention was to weigh each body before and after their passing to determine any differences in mass. Initiating the experiment, in the company of four other doctors, MacDougall carefully measured the weight of the first patient moments before their last breath.

And then again, after the patient’s death.

The experiment continued onto the next patient, with the same results. A quote from The New York Times.

‘The instant life ceased the opposite scale pan fell with a suddenness that was astonishing – as if something had been suddenly lifted from the body.  Immediately all the usual deductions were made for physical loss of weight, and it was discovered that there was still a full ounce of weight unaccounted for’.

Everything was taken into account, from the air in the lungs to bodily fluids, and the loss in weight remained unexplained. Following the experiment and post consultation with the other attending physicians, it was determined that the average weight loss of each person was ¾ of an ounce.

MacDougall’s conclusion was that this very slight change in weight might be attributed to the instance of the soul departing the body, and if this were the case, calculated the weight of the human soul to be..

21 grams.

Alejandro Gonzáles Iñárritu directed a film in 2003 called 21 Grams, which finishes with a monologue.

How many lives do we live. 



How many times do we die. 



They say we all lose 21 grams at the exact moment of our death. 



Everyone. 



How much fits into 21 grams. 



How much is lost. 



When do we lose 21 grams. 



How much goes with them. 



How much is gained. 



How much… is gained. 

21 grams. 



The weight of a stack of five nickels. 



The weight of a hummingbird. 



A chocolate bar. 



How much do 21 grams weigh.

The Reunion of the Soul and the Body at the Resurrection (1808)

William Blake