Rudolf Steiner 
Theosophy [EPUB ebook] 
An Introduction to the Supersensible Knowledge of the World and the Destination of Man

It must be recognized that a knowledge of the spiritual world, not merely a knowledge gained by treading the path, but also a knowledge acquired through grasping the truths of spiritual science with the unprejudiced, healthy human intellect, leads also to a higher moral status in life, to a knowledge of sensory existence that is in accord with the truth, to certainty in life, and to inward health of the soul.