All that is self-constituted is perpetual. For example, it must have an existence which is self-contained. Every soul is an incorporeal substance and separable from body. The results apply equally to cognition's home, the soul. The soul, being self-knowing, must also be incorporeal and separable from the body.
Every soul is indestructible and imperishable.
It is therefore indestructible and imperishable. Proclus will proceed to interpret this result as support for a theory in which the soul undergoes an unceasing cycle of reincarnations. In the next chapter we will begin a modern critique of Proclus' argument for immortality. The Fihrist , A.D. 987. Apparently Proclus' original text had been translated and was in circulation among Arab scholars by that time.