"It is emphatically true of these themes," I remarked, after a long rambling talk, half reverie, half reason, "that language conceals the ideas, or, rather, the imaginations they evolve; for the word idea implies something more tangible than vagaries which the Greek poet would have called 'the dream of the shadow of smoke.' But yet more unsatisfactory than the impotence of the type is the obscurity of the thing typified. We can lay down no premises, because no basis can be found for them,--and establish no axioms, because we have no mathematical certainties. Objects which present the assurance of palpable facts to-day may vanish as meteors to-morrow. The effort to crystallize into a creed one's articles of faith in these mental phantasmagoria is like carving a cathedral from sunset clouds, or creating salient and retreating lines of armed hosts in the northern lights. Though willing dupes to the pretty fancy, we know that before the light of science the architecture is resolved into mist, and the battalions into a stream of electricity." "Not so," replied Vilalba. "Your sky-visions are a deceit, and you know it while you enjoy them. But the torch of science is by no means incendiary to the system of psychology. Arago himself admits that it may one day obtain a place among the exact sciences, and speaks of the actual power which one human being may exert over another without the intervention of any known physical agent; while Cuvier and other noted scientists concede even more than this." "Do you, then, believe," I asked, "that there is between the silent grave and the silent stars an answer to this problem we have discussed to-night, of the inter-relation between spirit and matter, between soul and soul? To me it seems hopelessly inscrutable, and all effort to elucidate it, like the language of the Son of Maia, 'by night bringeth darkness before the eyes, and in the daytime nought clearer.' I shall as soon expect to wrest her buried secrets from the Sphinx, or to revive the lost mysteries of the Egyptian priesthood."