This is the second part of a three-part series looking at logical arguments which have been raised against the existence of a supernatural personal devil. In the previous installment we looked at the empirical argument, which denies the devil's existence on the basis of a lack of empirical evidence for his existence. We saw that this argument requires the professing Christian to maintain a double standard, because s/he is happy to believe in angels and the Holy Spirit in the absence of empirical evidence for their existence.
Another argument claims that if a supernatural, personal devil existed this would contradict the theistic view of God as omnipotent and absolutely good. If the devil roamed about wreaking havoc, this would imply either that God is unable to stop him (and therefore not omnipotent) or else that God is unwilling to stop him (and therefore not absolutely good). Thus we must either reject theism or else reject the existence of the devil.
In fact, this is nothing other than a special case of the argument from evil which has long been used by atheists to argue against the existence of God! The atheistic argument from evil goes like this:
1) A theistic (all-powerful and all-good) God would not allow evil to exist.
2) Evil exists.
3) Therefore, no theistic God exists.
The argument against the devil’s existence basically replaces ‘evil’ in the above syllogism with ‘the devil’ and then observes that if we assume the devil’s existence (premise 2) we arrive at an unacceptable conclusion, namely atheism. However, this argument is again self-defeating. If the above syllogism is valid then no theistic God exists, regardless of whether there is a devil. Hence, every professing Christian must reject the syllogism, and to use the very same logic to argue against the devil's existence would appear inconsistent.
On what basis do theists reject the above syllogism? The theist admits premise 2 but denies premise 1, at least with respect to every kind of evil whose existence he or she admits, such as nuclear disaster-inducing tsunamis and genocidal tyrants. How can theists deny premise 1? One approach is to argue that God may allow evil because in so doing he allows a greater good to be achieved than would be possible otherwise. This greater good could include things like free will, the prevention of even greater evils, character development through trials, and the joy of deliverance and salvation.
If a theist wanted to rework the syllogism above into an argument against the devil, s/he would need to show that, while premise 1 does not hold for evil in general, or for specific instances of evil such as tsunamis and tyrants, it does hold for a supernatural personal devil. The question is, why would premise 1 hold for a supernatural personal devil if it does not hold for any other kind of evil? What is it about the devil that makes it impossible for God to allow his existence but possible for God to allow Hitler's existence? Is it that a supernatural devil would be more evil and more powerful than Hitler? How far then does a being have to slide on the ‘evil scale’ or ‘power scale’ before it stops being morally justifiable for God to allow his existence and becomes morally reprehensible?
Put another way, if God could allow a being as evil and powerful as Hitler to exist because doing so allowed some greater good to be achieved, then couldn't God do the same for an even more evil and powerful being such as the devil? To deny that God could is to deny his omnipotence. Thus, ironically, the argument which sought to uphold theism actually undermines it.
The only other conceivable way to rescue premise 1 in the special case of the devil is to argue that the natural/supernatural or human/angelic distinction fundamentally alters the logic. However, such ontological distinctions are of no logical consequence. An archangel and an ant are equally powerless to thwart the prerogatives of an infinite God.