What is immortal must be solid because it cannot be affected by blows, so that nothing can pierce it or break it through. This I call wisdom. It has no beginning nor ending. It cannot be stretched for it fills all space and there is no place to receive it. So it is like space, and the universe is eternal. But mind is not solid because it is porous; or there is space in all compound beings so that forces applied to it deadens or dissolves it and it passes off in air. Now as the soul is the mind, it must be of matter. If you think she can fly to God and be out of danger you are mistaken for she sickens with disease of the body and things torment her. She is disordered by fear and vexed by cares and the consciousness of crimes committed years ago pierce her through and her crimes are overtaken by the fear of an endless torment after death. All this goes to show that man according to Pagan philosophy is made up of just what the Christians make man in our day. The soul is not a solid because it affects the body and is affected by it; therefore it takes up space like the body. The doctrine of Pythagoras was that the souls were shifted out of one animal into the body of another. Then they must be changed, for when the soul of man entered the dog, the soul must change or the dog would be a man, for the soul must agree with the body which it enters. Lucretius says to his friend, If it be pretended that the human soul passes into human bodies, a man at full age plays the fool in the child. Now if the mind is weak in a weak body, then the mind changes and so things that can be so easily changed cannot be immortal.