The history of the idea of immortality is a good example of our congenital inability to perceive realities otherwise than reshaped and worked over by the understanding. The idea of immortality is born of belief in the double. In sleep, and while the body is inert, there is a part of man that stirs, that travels, that fights, that eats, enjoys or suffers, exhibits all the phenomena of life. This part of man, this double of man, this astral body, survives the decomposition of the material body, whose habits and needs it keeps. Such, doubtless, is the origin of the belief in what, since Hellenism, we call the immortality of the soul. In an earlier stage, the Egyptian religion was based upon the theory of the double. It was for doubles, and not for souls, that first real, and later symbolic, food was placed in the tombs. But the Egyptian religion was already charged, in addition, with the idea of justice, of equilibrium. The doubles were weighed in the scales of good and evil. Ethical metaphysics had obscured the primitive idea of immortality, which is nothing but the idea of indefinite duration. For theologians, for philosophers--if there still be any to profess these honest doctrines--for the common run of men, the idea of immortality, or of the future life, is intimately connected with the idea of justice. Eternal happiness is a compensation accorded human sorrows. There are also--but these are for theologians only--personal torments to punish infractions of priestly orders, which tortures are, moreover, an additional recompense for the good, and a guarantee against promiscuity. We have here an aristocratic selection, but one based upon the idea of good and bad, instead of upon that of strength and weakness. These strange reversals of values enraged Nietzsche. They should be accepted as at least transitory consequences of civilized man's sensibility. Primitive man, whose nervous vibrations are few, and whose intelligence is passive, feels suffering, though dully, but does not feel injustice, which is moral suffering. To encounter a similar state we must cross the middle regions, and question a Goethe, a Taine or a Nietzsche--men in whom intelligence has finally conquered by its very excess, repelling the pleadings of pity and the sentimental pitfalls of justice. If the idea of immortality had been born in a superior intelligence, it would have differed only by its greater logic from the brutal conceptions of primitive humanity.