Thus the soul was generally taken for the origin and the cause of life, for life itself. That is why all known nations long imagined that everything died with the body. If one can disentangle anything in the chaos of ancient histories, it seems that the Egyptians at least were the first to distinguish between the intelligence and the soul: and the Greeks learned from them to distinguish their +nous+, their +pneuma+, their +skia+. The Latins, following their example, distinguish _animus_ and _anima_; and we, finally, have also had our _soul_ and our _understanding_. But is that which is the principle of our life different from that which is the principle of our thoughts? is it the same being? Does that which directs us and gives us sensation and memory resemble that which is in animals the cause of digestion and the cause of their sensations and of their memory? There is the eternal object of the disputes of mankind; I say eternal object; for not having any first notion from which we can descend in this examination, we can only rest for ever in a labyrinth of doubt and feeble conjecture. We have not the smallest step where we may place a foot in order to reach the most superficial knowledge of what makes us live and of what makes us think. How should we have? we should have had to see life and thought enter a body. Does a father know how he has produced his son? does a mother how she conceived him? Has anyone ever been able to divine how he acts, how he wakes, how he sleeps? Does anyone know how his limbs obey his will? has anyone discovered by what art ideas are marked out in his brain and issue from it at his command? Frail automatons moved by the invisible hand which directs us on this stage of the world, which of us has been able to detect the wire which guides us? We dare question whether the soul is "spirit" or "matter"; if it is created before us, if it issues from non-existence at our birth, if after animating us for one day on earth, it lives after us into eternity. These questions appear sublime; what are they? questions of blind men saying to other blind men--"What is light?" When we want to learn something roughly about a piece of metal, we put it in a crucible in the fire. But have we a crucible in which to put the soul? "The soul is _spirit_," says one. But what is spirit? Assuredly no one has any idea; it is a word that is so void of sense that one is obliged to say what spirit is not, not being able to say what it is. "The soul is matter," says another. But what is matter? We know merely some of its appearances and some of its properties; and not one of these properties, not one of these appearances, seems to have the slightest connection with thought.