"Having a soul" is likely a natural cognitive bias, which is very likely to predate any actual religion or belief system. It is "witnessed" personally during ne

"Having a soul" is likely a natural cognitive bias, which is very likely to predate any actual religion or belief system. It is "witnessed" personally during near-death experiences, just like karma is "witnessed" in other altered states of consciousness. These states are relatively rare, but frequent enough to fill a void of not knowing what happens after death in almost all tribes and societies. Then the emotional part kicks in: it's easier to survive a loss of somebody if one believes in that kind of after-death experience. Of course, religions and this kind of grass-root spiritual beliefs are mutually reinforcing too, but the latter seems to predate (and direct) the former.