This is, we acknowledge the greatest and most serious argument against our system. But we must hasten to add, that if this difficulty did not exist, if the remembrance of a life anterior to our present existence were always before us, the doctrine of plurality of lives would need no reinforcement from the proofs for which we appeal to argument, to the facts of observation, and to logical induction. It would be plain before our eyes, it would be self-evident. All our merit, all our task in this work, is to endeavour to procure admission of the plurality of existences, though we have no remembrance of our past lives. We have already treated this question incidentally, and we will now summarize all that has been advanced in former chapters to explain the absence of recollection of our past existences. The soul in its first human incarnation, if it proceeds from a superior animal, could not possess memory, because in animals that faculty has a small range, and brief duration. If a second or third human incarnation is in question, the difficulty is serious, because it implies that the man who has lived and who is born again, has forgotten his previous life. But, in the first place, this forgetfulness is not absolute. We have remarked before that in the human soul certain results of impressions received prior to the terrestrial life always linger. Natural aptitudes, special faculties, vocations, are the traces of impressions formerly received, of knowledge already acquired, and, being revealed from the cradle, cannot be explained otherwise than by a life gone by. We have lost the remembrance of the facts, but there remains the moral consequence, the _resultant_, the philosophy, so to speak, and thus the _innate ideas_ indicated by Descartes, which exist in the soul from its birth, and also the _principle of causality_, which teaches us that every effect has a cause, are explained. This principle can only be derived from facts, because an abstraction can only be based upon concrete facts, upon accomplished events, and this abstraction, or this metaphysical idea, which we have from our birth, implies anterior facts, which must belong to a past life. We have already said that when the soul gives free course to reverie, it beholds mysterious and undefined spectacles, which seem to belong to worlds which are not quite unknown to us, but in no wise resembling this earth. In this vague contemplation there is something like a confused remembrance of an anterior life. The love which we bear to flowers, plants, and all vegetation, may be as we have already pointed out, a grateful recollection of our first origin.