Personally I don't believe that a soul per se exists. I believe in the mind and it's functions and foibles, and I feel that psychology and therapy lends itself to understanding the mind.

The mind being, at best, the flow of conscious and unconsciousness; emotional and cognitive states. It is never the same and always in flux. The brain is meat; it's the hard drive and the mind is the central processor that uses the data in the brain to create our world.

And personally, I also feel the unified theory already exists. We just don't understand or know how to get all the links to work.