AnAtheist:
Assume a set of all things, that can be known. You can then construct a power set of that set (i.e. knowing, that you know all). That power set has more elements than the original set, thus the original set could not include *all *knowable things. q.e.d.
Furthermore you get contradictions when you make self-referencing statements like the one with the stone. Russel’s antinomy is another good example. Or the work of Gödel.
This arguement is starting from a falacy. It is based on a limitation which you are putting on God. Christianity teaches that God is omnipotent and omniscient. That means that he knows all there is to know and that he can do what ever he wants. You are starting from the assumption that there is a limit to the knowledge and power of God.
Second, Christianity teaches that God created everything from nothing. So, there was nothing that was before he created it, other than himself. Now, to claim that there is power that God does not have you must come to the conclusion that God did not create everything and that there is some power outside of himself that did so or just was.
That is against Christian doctrine, so your arguement is false, unless of course you want to beat a punching bag.
Next, the rock statement, “God can’t create a rock he can’t lift, so there is no god.” This is also false. Why? Because it makes a presuption that God has a limit to what he can lift. God can lift any weight. If you put 1 trillion pounds on a curl bar and say, “God lift that”, he will with out a problem. If you add another 1x10 to the 1 with a million zero’s, he will still lift it with out any problem. No matter how much weight you put on the bar, God can curl it with ease.
You are unknowingly putting a limit on the strength of God when you say he can’t make a stone he can’t lift, because you are implying that there is some weight he can’t lift. God has the ability to make a stone of any weight. Since God can lift any weight, and he can make any weight, the question is invalid.
You also can not put God’s omnipotence against itself, and claim God is not omnipotent. That is a fallacy. To say that God is not omnipotent because he can lift any rock and that it is not possible to make a stone that God can not lift, is fallacy. God is one, there is no outside force dictating a limit on his power. There is only his power that says he can do anything.