formation; but we are speaking of a secondary formation in the logical, not the chronological, sense of the word. V But how does it come that men have believed that the soul survives the body and is even able to do so for an indefinite length of time? From the analysis which we have made, it is evident that the belief in immortality has not been established under the influence of moral ideas. Men have not imagined the prolongation of their existence beyond the tomb in order that a just retribution for moral acts may be assured in another life, if it fails in this one; for we have seen that all considerations of this sort are foreign to the primitive conception of the beyond. Nor is the other hypothesis any better, according to which the other life was imagined as a means of escaping the agonizing prospect of annihilation. In the first place, it is not true that the need of personal survival was actively felt at the beginning. The primitive generally accepts the idea of death with a sort of indifference. Being trained to count his own individuality for little, and being accustomed to exposing his life constantly, he gives it up easily enough.[864] More than that, the immortality promised by the religions he practices is not personal. In a large number of cases, the soul does not continue the personality of the dead man, or does not continue it long, for, forgetful of its previous existence, it goes away, after a while, to animate another body and thus becomes the vivifying principle of a new personality. Even among the most advanced peoples, it was only a pale and sad existence that shades led in Sheol or Erebus, and could hardly attenuate the regrets occasioned by the memories of the life lost. A more satisfactory explanation is the one attaching the conception of a posthumous life to the experiences of dreams. Our dead friends and relatives reappear to us in dreams: we see them act, we hear them speak; it is natural to conclude that they continue to exist. But if these observations were able to confirm the idea after it had once been born, they hardly seem capable of creating it out of nothing. Dreams in which we see departed persons living again are too rare and too short and leave only too vague recollections of themselves, to have been able to suggest so important a system of beliefs to men all by themselves. There is a remarkable lack of proportion between the effect and the cause to which it is attributed.