A perfectly evil human society is unthinkable: it would be self-destructive. We therefore deny that any society of absolutely evil spirits could be permanent. Evil in short, cannot be a unifying spiritual principle: to put it colloquially, there must be some good in the Devil or he must ultimately destroy himself. It is certain that the Devil cannot be the creative source of evil in the same way that God is the creative source of good.

Spiritualism and the Christian Faith (1918)