Originally Posted by
RichardHresko
Satan cannot be pure evil, for if he were pure evil he would cease to exist.
1) All of God's creations were good at the time of their creation.
2) Therefore everything that exists has some goodness.
2b) To have existence is therefore to partake of some good.
3) Evil is the corruption of goodness, and has no independent existence.
4) Anything that has been completely corrupted would cease to exist.
5) Satan exists.
6) Satan can not be purely evil.
QED.
The essence of this argument is based on de libero arbitrio by Augustine.