"Body', 'soul', and 'spirit' may designate phenomenal domains which can be detached as themes for definite investigations; within certain limits their ontological indefiniteness may not be important. When, however, we come to the question of man's Being, this is not something we can simply compute by adding together those kinds of Being which body, soul, and spirit respectively possess--kinds of being whose nature has not as yet been determined. And even if we should attempt such an ontological procedure, some idea of the Being of the whole must be presupposed."