By the commission of such a sin the most powerful intellect becomes inevitably committed to further enormities. Except by neglecting to distinguish between sight and hearing, the effects, and light and sound, their respective causes, it would surely have been impossible for Professor Huxley to come to the strange conclusion that if all living beings were blind and deaf, 'darkness and silence would everywhere reign.' Had he not himself previously explained that light and sound are peculiar motions communicated to the vibrating particles of an universally diffused ether, which motions, on reaching the eye or ear, produce impressions, which, after various modifications, result eventually in seeing or hearing? How these motions are communicated to the ether matters not. Only it is indispensable to note that they are not communicated by the percipient owner of the eye or ear, so that the fact of there being no percipient present cannot possibly furnish any reason why the motions should not go on all the same. But as long as they did go on there would necessarily be light and sound; for the motions are themselves light and sound. If, on returning to his study in which, an hour before, he had left a candle burning and a clock ticking, Professor Huxley should perceive from the appearance of candle and clock that they had gone on burning and ticking during his absence, would he doubt that they had likewise gone on producing the motions constituting and termed light and sound, notwithstanding that no eyes or ears had been present to see or hear? But if he did not doubt this, how could he any more doubt that, although all sentient creatures suddenly became eyeless and earless, the sun might go on shining, and the wind roaring, and the sea bellowing as before?