Even at that the column is something of a straw man since no serious theologian or philosopher subscribes to the definition McGinn critiques.
After arguing that God cannot have certain powers, like the power to digest food (because He has no digestive system), McGinn concludes that God is not all-powerful. He lacks powers that other beings (e.g. animals) have, and if He had those powers then He would be an embodied being and thus not God. Therefore, either He's not all-powerful or not really God. The concept of an all-powerful God, he surmises, is incoherent.
McGinn finishes his essay with this:
The difficulty for God is to specify what kind of omnipotence he is supposed to possess. (Actually, McGinn must mean here that this is a difficulty for the theist, not for God. God has no obligation to specify anything of the sort.)It's hard to tell what McGinn's point is here. He's a world-class philosopher. Surely he knows that no one, at least no theistic philosopher, believes that God has the power to do just anything at all. By "omnipotence" theists mean that God can do whatever is not inherently absurd, is logically possible to do, and consistent with His nature.
And the dilemma is obvious: either he has powers that do not properly belong to his nature as divine, or he lacks powers that other things possess, thus being less than all-powerful.
The concept of an all-powerful being is actually, when you think about it, incoherent. To be a thing of a certain type is necessarily to have a limited range of powers, because powers and natures go hand in hand.
He cannot, for example, make a dog that's a better rhetorician than a cat or make one color sound better than another. Nor can He create a world in which He doesn't exist, nor take pleasure in evil.
Given the foregoing definition, then, what God can do is create any logically possible universe, a feat or capability that requires unimaginable power. This power further entails that He has the power to create capacities that He Himself does not exhibit because they would be inappropriate to, or incompatible with, the kind of being He is.
Nevertheless, even though He doesn't "possess" these "powers" Himself, His power to create them is itself an enormous potency. For instance, He creates green plants which have the "power" to photosynthesize and creates as well the process of photosynthesis itself. That He Himself can't photosynthesize is hardly a limitation on His power.
In fact, it's beyond ridiculous to claim, as the title of McGinn's article does, that God's "lack" of such powers is somehow a proof that God doesn't exist.
