Authors:

...if we expended all our energies solely on taking care of our own needs we would stop growing. In that respect what we call "soul" can be viewed as the surplus energy that can be invested into change and transformation. As such, it is the cutting edge of evolution.

Mihaly Csikszentmihalyi (2004). “Good Business: Leadership, Flow, and the Making of Meaning”, p.113, Penguin
...if we expended all our energies solely on taking care of our own needs we would stop growing. In that respect what we call soul can be viewed as the surplus energy that can be invested into change and transformation.