One common objection (or jeer) held against theism is the objection that can be called “God and the rock.” The objection is generally posed as a question, running somewhere along the line of, “Can God create a rock so big that he himself can’t lift it?” The paradox is aimed at showing that an omnipotent being is logically impossible given that neither the affirmative nor the negative response safely preserves the omnipotence of God. A syllogistic form of the paradox can be written as follow:
A. Either the omnipotent God can or cannot create a rock that he can also himself lift.
B. If God can create a rock that God cannot lift, then there is a task which God could not perform, namely lifting the rock.
C. If God cannot create a rock that God cannot lift, then there is a task which the omnipotent God cannot perform, namely creating the rock of such poundage.
D. Thus, there is at least one task that the omnipotent God cannot do.
E. Conclusively, God is not omnipotent
The common apologetical response to this paradox is that the objection holds a logical contradiction insofar as the two tasks concerned, and being unable to perform a logically contradictory task is no limitation on God’s power because it is within God’s nature to follow an internal system of metaphysical consistency is part of His nature. While this view is held widely by brilliant philosophers, Kreeft, Swineburn, St. Thomas Aquinas to name a few, there are still some disputes as to its cogency, and Cartesian philosophy does not fancy this line of reasoning. While I do not think that the Cartesian line of thought in this matter to be intelligible, I will not venture a systemic criticism (although God can both exist and not exist can be the first line of such criticism). That being said, there is no logical inconsistencies within the paradox itself and thus such an attempt at responding to the paradox by seeing it as a logical contradiction seems fruitless to me.
The problem seems to stem from premises B and C where the commitment to the premises as they stand seems to imply two different tasks which the omnipotent being cannot complete. Yet, if we were to replace the premises with one that reads: “If God can create a stone, then God can lift it.” The seeming problem with the premises vanishes with this replacement and we are left with a conclusion that does not negate the omnipotence of God. Hence, the most plausible response to the “God and rock question”, it seems to me, is one that I encountered years ago by Wade Savage. Savage proposes that one can answer “no” to the question of God and the rock and is still not forced to forgo God’s omnipotence. Savage proposes that we take this argument in abilities to perform tasks and split them into two different persons in order to see that there is actually no problem in answering “no”.
Consider this example:
Let Jack be the one who can create rocks and Jill be the one to lift them. There are only two instances where it would be true to say that either Jack or Jill is limited in power. Instance (i): Jack cannot create any rock heavier than 90 poundage, but Jill can lift rocks of any poundage. In this instance, Jack can be said of as being limited in power because he cannot create a rock heavier than 90 poundage. Instance (ii): Jack can create a rock of any poundage, but Jill is unable to lift any rock heavier than 90 poundage. In this stance, Jill can be said as being limited in power because she cannot lift any rock heavier than 90 poundage.
Yet the same limitation cannot be said of Jack or Jill if Jack can create a rock of any poundage and Jill can lift any poundage. In this instance (iii), any rock that Jack creates Jill can lift. If this is so, then one cannot conclude that there is any limitation within Jack’s power to create rocks since any rock of any poundage that he creates Jill can lift. Thus, to say that Jack cannot create a stone so heavy enough that Jill cannot lift is not a limitation on Jack’s power. This is so because in this instance (iii) is completely different from the other instances (i) and (ii). The limitation of Jack’s power is only an illusion produced by the word ‘cannot’, but, again, as I have pointed out above, this illusion vanishes when we rephrase it to “Jack can create any size rock and Jill can lift any rock that Jack creates”.
Thus, if we extend the above example to God and combine the two powers within God’s omnipotence as both the creator and lifter of the same rock, we find that the answer “no” to the central objection of the “God and the rock” paradox does not leave God limited in power.