>Interesting... though, judging by what people wrote there, it's too much religion related for my taste. I may still look it up.
I think it refers to the belief that the soul has a weight. Somebody claimed it weighed 21 grams - see
http://www.snopes.com/religion/soulweight.asp - but the investigation was not very accurate.
Even for many who do believe in a soul (like me), this is very doubtful, the soul not being exactly part of this mortal world.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)