For example, Einstein tells us that what we call the “ether” has no existence. It is merely a “void.”—But how can we call that void which contains something—undulations, to wit? “Nay!” you argue; “the undulations traverse the ether, but they are not it. The ether is a non-entity. It has no existence. It is nothing.” To which I reply: “But ‘nothing’ is an absolute term. It means ‘no thing.’ How, then, can undulations, or anything else for that matter, pass through nothing?” “What nonsense!” you cry; “this kind of verbal poser is just the silly old metaphysicians’ parlour game of playing with words.” I know it is. But the word-play has its uses. It demonstrates to us that words, language, logic, all alike, fail our thought, not so much because those instruments are limited in power as because the thought itself is lacking in precision and comprehensiveness. It is when our word-play probes the expression that the vagueness of the idea is made manifest. Our foil, even with the button on, goes clean through the phantom. The mind, in short, has not absorbed, nor can it absorb, the _fact_. We seize a glass of water to drain it, and presently, like Alice, we find ourselves swimming about in an ocean! Obviously the universe _is_ beyond our comprehension, a conclusion desperate if you like, yet undeniable. But how very annoying it is, after all our heavy labour, to hear the ancient scoff of Zophar the Naamathite still ringing triumphant: “Canst thou by searching find out God? Canst thou find out the Almighty unto perfection?” (Still we mean to go on trying!) Yet of all the senses none surely is so mysterious as that of smell. For, as we have shown, the nature of the emanations that stir it to activity is still unknown; the simple structure of its end-organ confronts us, like a sphinx, with silence; and after the reception of the stimulus in the olfactory lobe of the brain its further connections and communications still remain unsurveyed, albeit, as I have already so amply displayed, its effects upon the _psyche_ are both wide and deep, at once obvious and subtle. CHAPTER IX DUST OF THE ROSE PETAL By way of relief from the exacting mental strain of the last chapter, I have thought that the reader who has got this length might be grateful for something more simple, and so it is not altogether egotism that leads me to finish up with a few of the olfactory pictures I cherish. Before proceeding with the subject-matter proper of the chapter, however, let me put in a plea for the conscious cultivation of the sense of smell. But little more, I take it, is needed in this way than to pay attention to the olfactory sensations that reach us, for the very fact of taking note of them is sufficient probably to increase the power and delicacy of olfaction, this being always the effect of the mental process known as attention.