The absolute and complete certainty, on the one hand, that death is a complete, definite, irrevocable annihilation of personal consciousness, a certainty of the same order as the certainty that the three angles of a triangle are equal to two right angles, or, on the other hand, the absolute and complete certainty that our personal consciousness is prolonged beyond death in these present or in other conditions, and above all including in itself that strange and adventitious addition of eternal rewards and punishments--both of these certainties alike would make life impossible for us. In the most secret chamber of the spirit of him who believes himself convinced that death puts an end to his personal consciousness, his memory, for ever, and all unknown to him perhaps, there lurks a shadow, a vague shadow, a shadow of shadow, of uncertainty, and while he says within himself, "Well, let us live this life that passes away, for there is no other!" the silence of this secret chamber speaks to him and murmurs, "Who knows!..." He may not think he hears it, but he hears it nevertheless. And likewise in some secret place of the soul of the believer who most firmly holds the belief in a future life, there is a muffled voice, a voice of uncertainty, which whispers in the ear of his spirit, "Who knows!..." These voices are like the humming of a mosquito when the south-west wind roars through the trees in the wood; we cannot distinguish this faint humming, yet nevertheless, merged in the clamour of the storm, it reaches the ear. Otherwise, without this uncertainty, how could we live? _"Is there?" "Is there not?"_--these are the bases of our inner life. There may be a rationalist who has never wavered in his conviction of the mortality of the soul, and there may be a vitalist who has never wavered in his faith in immortality; but at the most this would only prove that just as there are natural monstrosities, so there are those who are stupid as regards heart and feeling, however great their intelligence, and those who are stupid intellectually, however great their virtue. But, in normal cases, I cannot believe those who assure me that never, not in a fleeting moment, not in the hours of direst loneliness and grief, has this murmur of uncertainty breathed upon their consciousness. I do not understand those men who tell me that the prospect of the yonder side of death has never tormented them, that the thought of their own annihilation never disquiets them. For my part I do not wish to make peace between my heart and my head, between my faith and my reason--I wish rather that there should be war between them!