Using a computer as an analogy for the nervous system, the brain is all manner of computing hardware, the mind is all the software running on it, and the soul is just a fraction of that software. Most of the software running in the mind deals with decision making, behaviorism, personality, creativity, etc. What I would refer to as the soul though, is the interpretation of ones self that no one could understand other than them self. As the way one thinks may drastically change, and ones personality may change, and on the outside may be a completely different person, their soul still contains all that is them. It isn't so much just a memory, but all memories condensed into one image of the self. One musn't recall on all memories to conjure up this image, it's embedded there always emboldening the self. However, it is just a part of the mind, which is but a product of the body. When the body ceases to function, the mind ceases to exist, and along with it, the soul. What I've found is rather ironic, and poetic though is that the soul when looked at in this way, is actually the only part of a person that will disappear entirely. The mind of a man may go on with his words, and the body of a man will live on in all manner of biological form, but the soul was only known to him, and only ever will have been.