"The immaterial essence, animating principle, or actuating cause of an individual life." Webster's Dictionary.

"...the human soul is a divine non-substance. A spirit that permeates our flesh, dwells in our conscious, and rules our subconscious self. It makes us cling to life even when we no longer want to embrace it. It makes us hope in the most desperate of circumstances. It gives our dream shape, our inspiration form, our love its timeless beauty." From The Cartesian Machine.
http://www.amazon.com/The-Cartesian-M...