Omniscience Argument Revisited

[Rational AKD]

you'll have to excuse me, I didn't realized you changed your entire argument within the recent comments of the thread (I didn't think you would concede how flawed your original argument was so quickly). but anyways your fourth premise then is "it is impossible for an omniscient being to know it is truly omniscient." this, however, changes more of the argument more than you know or at least seem to realize. if you were to end with that premise, then I would agree with your argument... but you originally wanted to say something a little more substantive than that. P5 and C2 of the argument go on to say that it is therefore impossible for God to exist as defined with the quality of omniscience. as you said, this argument now doesn't aspire to prove omniscience itself is impossible as you stated here:

So really, this argument isn't so much an argument against the POSSIBILITY of omniscience, rather it's an argument against ever knowing that one is omniscient.

so if you're argument doesn't show it's impossible to be omniscient, you also can't conclude God who has this attribute doesn't exist. you can't logically arrive at C2 from revised C1 and P5.

Further, it's not hard to think of thought experiments of things God has no way of knowing by his own power, yet could know.

do you even listen to yourself? God has no way of knowing yet could know? if he has no way of knowing he can't know. but go ahead, try to come up with some knowledge God can't possibly know that's not impossible to know. this should be amusing.

ok I don't really see any more contentions with your argument as it now is. the only thing is that because you are not arguing against the possibility of omniscience, you are not making a case against the existence of God. if you want to end your argument with the conclusion "God can't possibly know whether he is truly omniscient" I have no contention. but that's not a very controversial point you're trying to establish.