When getting into a debate with most christians about their deity doing anything that it wants to, one of the most common tactic that most atheist (including myself once) use to try to disprove the christian god is ask questions like "Can God Create a Rock so heavy that he cannot move it?" or "Can God create a rock so heavy that he cannot lift it?"
Now I admit that questions like those can be pretty damn convincing. Especially since some fundamental christians claim that their so-called "god" is omnipotent and can do anything it damn well please. If this "god" created a rock that he cannot move, then that doesn't make it omnipotent, right?! However, when asking questions like those to try to stump christians, chances are, there is going to be some drawbacks going on here.
Like I said, it does sound convincing to ask questions like "Can God create a rock that he cannot lift?". However, there are drawbacks to questions like this.
Where I personally think that the "Rock" question falls down the most is the logical impossibility. It is asking whether or not this creator that the christians are talking about can do the logically impossible, which, in my opinion, is a totally meaningless question, and therefore of no use to anyone.
The reason why I say questions such as the "Heavy Rock" question is a logical impossibility because it involves what is called "fallacy of Contradictory Premises", which means making one statement that contradicts itself.
For example when asking the "heavy rock" question involving the christian's creator's ability, we are virtually asking "Can god do something that it itself cannot do?" or "Can god do something that god cannot do?", and asking questions like that, besides that fact that it doesn't make any sense, is called a fallacy of Contradictory Premises (God's capabilities vs. God's incapabilities).
Another problem that I have with questions like the "heavy rock" question is that even without the "Fallacy of Contradictory Premises" the question itself still sounds illogical and stupid. Don't get me wrong, you can ask questions like the "heavy rock" question. However, just because a question can be asked does not mean that it has any value, nor it deserve any sort of response.
Does it make sense to ask questions like, "What is the color of Sunday?" or "What did the apple said to the strawberry?", or even "What do numbers smell like?" or "What does the sun taste like?"
That is the same with the question like "Can god create a rock so heavy that it cannot move it or lift it?"
Lets put it like this:
You can mix together a bunch of words to make a question look interesting and even valid, but if the question (or the words mixed together in a question and/or statement) is meaningless then what use is it? That, in my opinion, is the case with the "Heavy Rock" question. It is based on a logical impossibility and just becomes pointless mix of words.
In my humble opinion (note the word "humble"), if you really must use the "heavy rock' question to use as ammo against most christian arguments, be on the defensive side when using that question. When a fundie christian says something like "With God, all things are possible!" or something like that, then use the "Heavy Rock" question as an way to tell them that statements like that just doesn't cut it. However, when trying to use questions like that "heavy rock" question to try to disprove there beliefs, it can fall on you pretty quick.
Trust me, there over tactics that can used to disproved the christian ideas of a diety (Such as the Free will vs. omnipotent idea).
