The paradox of omnipotence presents the theist with the question “Can God create a rock so heavy that he cannot lift it?” This question, it is argued, cannot be answered in a way that is consistent with God’s omnipotence. If it is affirmed that God can create a rock so heavy that he cannot lift it then it must be conceded that God lacks the power to lift that rock. If it is denied that God can create a rock so heavy that he cannot lift it then it must be conceded that God lacks the power to create that rock. Either way, then, it must be conceded that there is something that God cannot do, that God is not omnipotent.

The most common theistic response to this problem is to argue that God cannot create a rock so heavy that he cannot lift it, but that this is entirely consistent with his being omnipotent. Omnipotence, it is suggested, is the ability to bring about any logically possible state of affairs.

The existence of a rock so heavy that God cannot lift it, it is suggested, is a logically impossible state of affairs. Omnipotence, though, does not entail the ability to bring about logically impossible states of affairs, and God’s omnipotence is therefore consistent with his being unable to create such a rock. The theist thus answers the question “Can God create a rock so heavy that he cannot lift it?” in the negative, but nevertheless maintains that God is omnipotent.

The distinction between logically possible and logically impossible acts has to do with the idea of self-contradiction. An act the description of which is self-contradictory is a logically impossible act. All other acts are logically possible.

Creating a square circle, for example, is a logically impossible act. Something is square only if it has exactly four sides. Something is a circle only if it has exactly one side. No object can have both exactly four sides and exactly one side. The idea of a square circle is thus self-contradictory, and so the act of creating a square circle is a logically impossible act.

For a being to be omnipotent, then, that being must be able to perform such feats as creating the universe, stilling the Sun in the sky, and restoring the dead to life, but need not be able to create square circles or know that which is false.

The theistic response to the paradox of omnipotence based on the idea that omnipotence is limited by logical possibility rests on the claim that it is logically impossible to create a rock so heavy that God cannot lift it. God, of course, is conceived of as a being who can lift any object, no matter how heavy; there is no rock so heavy that God cannot lift it, and there could be no rock so heavy that God cannot lift it. The existence of a rock that cannot exist, of course, is a self-contradiction, a logical impossibility. Creating such a rock, then, is not the kind of feat that a being must be able to perform if he is to be omnipotent. God’s inability to create such a rock would not, it seems, compromise his omnipotence.