"Only in vacuum lay the truly essential. The reality of a room, for instance, was to be found in the vacant space enclosed by the roof and the walls, not in the roof and walls themselves. The usefulness of a water pitcher dwelt in the emptiness where water might be put, not in the form of the pitcher or the material of which it was made. Vacuum is all potent because all containing. In vacuum alone motion becomes possible. One who could make of himself a vacuum into which others might freely enter would become master of all situations."