"Such is the relation, as I imagine it, of the soul to the body. A relation which we can imagine as existing momentarily in the case of the captain is the normal one in the case of the soul with its craft. As the captain is capable of a kind of movement, an amplitude of motion, which does not enter into his thoughts with regard to the directing of the ship over the plane surface of the ocean, so the soul is capable of a kind of movement, has an amplitude of motion, which is not used in its task of directing the body in the three-dimensional region in which the body's activity lies. If for any reason it becomes necessary for the captain to consider three-dimensional motions with regard to his ship, it would not be difficult for him to gain the materials for thinking about such motions; all he has to do is to call experience into play. As far as the navigation of the ship is concerned, however, he is not obliged to call on such experience. The ship as a whole simply moves on a surface. The problem of three-dimensional movement does not ordinarily concern its steering. And thus with regard to ourselves all those movements and activities which characterize our bodily organs are three-dimensional; we never need to consider the ampler movements. But we do more than use these movements of our body to effect our aims by direct means; we have now come to the pass when we act indirectly on nature, when we call processes into play which lie beyond the reach of any explanation we can give by the kind of thought which has been sufficient for the steering of our craft as a whole. "When we come to the problem of what goes on in the minute and apply ourselves to the mechanism of the minute, we find our habitual conceptions inadequate. The captain in us must wake up to his own intimate nature, realize those functions of movement which are his own, and in the virtue of his knowledge of them apprehend how to deal with the problems he has come to." _The Fourth Dimension_. How more accurately and eloquently could "the captain in us," momentarily aroused, give voice to his predicament, than in the words, "_Instead of the sublime and open world, the narrow prison of the breast_." DIRECT VISION