For me, the word soul refers to that part of me which is immortal, which will continue after I die, which may well have existed for some time even before I was born. The use (if you can even call it a use) is that it is immortal, does continue after death. Personally, I believe that everyone has one but that none of us are aware of our soul, can test our soul, make any use of it. It is not a tool, not a sense, not physical, not testable except in one instance. If we die and we do find
we continue to exist, then the soul existed.
Aslan is not a Tame Lion