The characteristic energy of pure Mind is change, and the more our mentality acquires elevation and organisation, the more this law of Mind assumes the aspect of a continual enlargement, improvement and better arrangement of its gains and so of a continual passage from a smaller and simpler to a larger and more complex perfection. For Mind, unlike bodily life, is infinite in its field, elastic in its expansion, easily variable in its formations. Change, then, self-enlargement and self improvement are its proper instincts. Mind too moves in cycles, but these are ever-enlarging spirals. Its faith is perfectibility, its watchword is progress.
Ref: The Synthesis of Yoga