Tho gloomy sounding, I do want to see it for as mentioned I'd not heard of this concept before re: soul substance = 21 grams. Be interesting to see if Hollywood :) expands more on Dr. Duncan MacDougall's hypothesis or incorporates present Physics into the theme.
As a side note:
You mention in your Cremation post... " And the religion of Hinduism is to burn, burn and burn the dead..."
Not sure what your emphasis of burn, burn, burn is to imply, but it is correct they have had a long tradition of cremation. Ayurveda which is India's ancient life science and system of holistic health care does not consider death as a finality. Death is only a transformation which is not different from other forms of transformation of energy. One example is of boiling water transforming into vapors, vapors when cooled down become liquid, and this liquid can be transformed into ice or vapors again. Nothing is really lost. (the Planck scale in Physics comes to mind here)
Death is a process of separation of soul from the material body and the "material body" goes back to the five elements it comes from. Ceremoniously burning their dead signifies that the material body, without the soul, should be given back to the five elements to maintain a balance in nature.
Interestingly, the dead body is not considered important. The real self of an individual is the soul which is considered indestructible, a mere essence without any substance."
This indestructible theme is also found in other hymns of the Vedas and the Bhagavad-Gita which sing the glory of the imperishable Self, Being, ultimate Reality which is the supreme, ultimate Absolute. They say: "Water cannot wet It nor can fire burn It. Wind cannot dry It and weapons cannot slay It. It is in front, It is behind, It is above and below. It is to the right and the left. It is all-pervading, the omnipresent, divine Being."
(not to convolute this side note but if our soul, in this Vedic concept, is an essence without any substance (bounded form)....omnipresent, which implies eternal, unbounded then it would be infinite would it not? And if this is correct however can infinity, if at all, be measured?)
Hummm, alot to consider. But thank you again John for introducing me to these ideas.