The theory of the soul was a matter on which philosophers focused particularly, since it showed them their own position within reality as well as their specific potential and goals. Thus the theory of the soul provides the psychological and epistemological prerequisites for Platonic theology and metaphysics (see Volume 7) as well as for ethics (see Volume 8). The individual problems dealt with include the definition and nature of the soul (151-158), origin and types of soul (159-163), parts and powers of the soul (164-170), preexistence, incorporation and freedom of the soul, its fate after death and the theory of transmigration. (171-180).