when the sperm enters the womb, that because of its physical constitution the sperm is prepared to receive the soul, which will be its director, and that it does not receive the soul merely because it is just a soul. In like manner a mirror which is free from rust reflects the image of a person standing close by. If the soul was one before the existence of bodies, how did it get divided? The division of that which has no magnitude or quantity is unintelligible. If, however, it is asserted that no division took place, still it will be an absurd assertion, for evidently the soul of Zaid is other than that of `Amr. If the two were one, the cognition of Zaid would be the cognition of `Amr, because knowledge is one of the essential attributes of the soul and the essential attributes enter into all the relations of the essence. And if the souls form a plurality, what is the cause of plurality? This cause cannot be found in matters or places or times or attributes, for there is nothing in all these to necessitate a difference of quality among the souls.