Through a series of innovative and thought-provoking studies, the author redefines spirituality as an experimental science that is rooted in concrete and empirically verifiable realities. "Though the fundamental laws of true spirituality remain constant," the author explains, "the practical application of its principles must be adapted to the intellectual and social developments of our time." In the quest to understand the metaphysical, one must not renounce reason and individual will, nor readily accept the arbitrary, for authentic spiritual laws always have a rational and satisfactory justification.