I've Only Heard It Two Ways
Tons of people have asked me this question and, as far as I know, its always been for one of two reasons. More than half of the time that people ask me this question, its meant as a goofy joke question to stump you sort of like asking if the chicken or egg came first or like telling someone to repeat a tongue twister. The goal is to have fun and watch people squirm through the riddle. In this case, you don't really need an answer. Talking it through is half of the fun and everyone is happy in the end.
Less often though, the question comes from a very different motive and goal. There are some people who have posed this question of me as if it were the deathblow to any and all arguments for God. They'll often add a word like, "BOOM!" at the end of the question to show just how much trouble you are in because they themselves have come up with the most clever, original, and effective proof that God is not real ever. I exaggerate a bit, but has anyone ever brought this question up to you like this? In this case, you kind of need to know how to respond in order to defend your faith. So what can we say?
At the source of the problem this question raises is the idea of God having limits. Christians and most monotheists in general believe that God is omnipotent, omniscient, and omnipresent. Those three things mean that God is all-powerful, all-knowing, and all-present. With that belief, it makes sense that most people would think that God doesn't have any limitations. But does He? Let's take a look from a Christian perspective...
God cannot lie
God did this so that, by two unchangeable things in which it is impossible for God to lie, we who have fled to take hold of the hope offered to us may be greatly encouraged. -- Hebrews 6:18
God cannot tempt others
When tempted, no one should say, "God is tempting me." For God cannot be tempted by evil, nor does he tempt anyone; -- James 1:13
God cannot change
Jesus Christ is the same yesterday and today and forever. -- Hebrews 13:8
I the LORD do not change... --Malachi 3:6a
Those are just a few examples of things that the Bible pretty clearly tells us that God cannot do. Red Flag! But if there are things that God can't do, doesn't that mean He is limited? Doesn't that mean He isn't all-powerful? Doesn't that mean He isn't really God?
Well, it depends on your definition of God. The Biblical and traditional Christian definition of God in terms of His omipotence (being all-powerful) is that God is able to do all His holy will (taken from Wayne Grudem's book Systematic Theology). From this understanding, it is perfectly acceptable to say that God is limited by His own nature and will. For example, God's nature is truthful and therefore He is limited by His own self and cannot lie.
On the other hand, if your definition of God is that He can do anything... well, you're kind of hard pressed to answer these sorts of questions. Instead, Christianity teaches that God is all powerful in the sense that He can do anything He pleases that would not violate His nature.
The Illogical Question
Another problem with this question is that if you look closely, it inherently doesn't make sense in terms of basic definitions. Part of the definition of God is that He is a being who is not limited in terms of physical strength. So then, what would a physical object have to look like or be like that God could not move? Please, define this object. What is it? How much does it weigh? When you begin attempting to define the object, you realize that no such object exists nor, by definition, could it exist. God (a Being not limited in terms of physical strength) and our mystery object (a physical object immovable by any being, especially God) are mutually exclusive things. Only one can exist by their very definitions.
There are other questions like this. Can God make a square triangle? Again, the very question does not make any real sense. These two terms are mutually exclusive. The very definition of a square includes the fact that it has four sides while the very definition of a triangle includes the fact that it has three sides. Likewise a square's angles must add up to 360 degrees while a triangle must add up to 180. By the very nature of the words in the question, such a shape cannot logically exist.
These questions make no sense because they are categorically formed in contradictory ways. It is like asking a bachelor who his wife is or asking what the color yellow tastes like. These questions are not real because the definitions of the words within them contradict each other.
So the question becomes, "Can God do illogical things?" or "Can God do things that don't make any sense?"
Thomas Aquinas, an old school theologian from the 13th century said it this way in his book Summa Theoligica.
“Whatever implies being and nonbeing simultaneously is incompatible with the absolute possibility which falls under divine omnipotence. Such a contradiction is not subject to it, not from any impotence in God, but because it simply does not have the nature of being feasible or possible. Whatever, then, does not involve a contradiction is in the realm of the possible with respect to which God is omnipotent. Whatever involves a contradiction is not within the scope of omnipotence because it cannot qualify for possibility. Better, however, to say that it cannot be done, rather than God cannot do it.” -- Thomas Aquinas
Personally, I have already shown that I have no problem saying that God is limited by His very nature. Because He is truth, He cannot lie. Because He is good, He cannot sin. I have no problem in also saying, "Because God is truth, He cannot do untrue things and because He is logical, He cannot do illogical things." Perhaps I am wrong. Perhaps God can indeed create an entirely different universe where geometry is different and square triangles can exist. If so, great. But if not, God is still God even though He is limited by His nature.
My, What A Limited Understanding We Have!
On Sunday, a friend of mine who is pretty smart reminded me that we have such a tiny portion of all of the knowledge, information, and facts that are out there in the universe. We still don't know exactly what causes gravitational attractions. We have yet to map out the connections in the human brain. Humans have set foot on the earth and the moon and nothing beyond that yet. In short, we don't know everything and we are not even close.
So, despite everything I just said, there is a part of me that has to humble myself and say I don't know. Perhaps there is a way for God to create a physical object that is infinitely heavy that even He can't lift and yet can lift as God at the same time. Perhaps there is such a thing as a square triangle and God knows exactly how to make it. Perhaps...
So, the majority of the time this question comes up, you can laugh and play along and imagine all of the goofy questions to pose when talking about God. Can God make a twin of Himself and then there are two Gods? Can God punch Himself so hard that He got hurt? Most of the time, just laugh and go for it.
But sometimes, people will pose these questions and actually think they have dealt Christianity a fatal blow. In those cases, remind them that Christians don't believe God has no limits whatsoever but that the Bible teaches that God's own nature and will limit Him. When we say God is all-powerful, we mean He is able to do anything He actually wants that doesn't go against His own nature. Also, point out the inherent contradiction in the question itself and tell them its like asking how tall the emotion sad is.
Fear not, the God of the ages has not been beaten by the question of a first grader. Next time you hear it, hopefully you'll remember this and respond well. Now go vote for next week's topic at the top right of the site!