The only light on this problem which we shall find, dwells in the realm of metaphysics rather than in the world of material reality. Ornament, more than any other element of architecture, is deeply psychological, it is an externalization of an inner life. This is so true that any time-worn fragment out of the past when art was a language can usually be assigned to its place and its period, so eloquent is it of a particular people and a particular time. Could we therefore detect and understand the obscure movement of consciousness in the modern world, we might gain some clue to the language it would later find. It is clear that consciousness is moving away from its absorption in materiality because it is losing faith in materialism. Clairvoyance, psychism, the recrudescence of mysticism, of occultism--these signs of the times are straws which show which way the wind now sets, and indicate that the modern mind is beginning to find itself at home in what is called _the fourth dimension_. The phrase is used here in a different sense from that in which the mathematician uses it, but oddly enough four-dimensional geometry provides the symbols by which some of these occult and mystical ideas may be realized by the rational mind. One of the most engaging and inspiring of these ideas is that the personal self is a _projection_ on the plane of materiality of a metaphysical self, or soul, to which the personal self is related as is the shadow of an object to the object itself. Now this coincides remarkably with the idea implicit in all higher-space speculation, that the figures of solid geometry are projections on a space of three dimensions, of corresponding four-dimensional forms. All ornament is in its last analysis geometrical--sometimes directly so, as in the system developed by the Moors. Will the psychology of the new dispensation find expression through some adaptation of four-dimensional geometry? The idea is far from absurd, by reason of the decorative quality inherent in many of the regular hypersolids of four-dimensional space when projected upon solid and plane space. If this suggestion seems too fanciful, there is still recourse to the law of analogy in finding the thing we seek. Every fresh religious impulse has always developed a symbology through which its truths are expressed and handed down. These symbols, woven into the very texture of the life of the people, are embodied by them in their ornamental mode. The sculpture of a Greek temple is a picture-book of Greek religion; the ornamentation of a Gothic cathedral is a veritable bible of the Christian faith. Almost all of the most beautiful and enduring ornaments have first been sacred symbols; the swastika, the "Eye of Buddha," the "Shield of David," the wheel, the lotus, and the cross.