Sorry, In response on my earlier post, I must remark that I do not deam it impossible to find a true answer on the question of the existence of god. In fact I am completely in doubt. Is there an objective truth? I don’t now. I define agnosticism as doubting the truth in religion as well as atheism. I define Atheism as renouncing the existence of god. Wich is rationally worth just as much as accepting the existence of god. And finally I define theism as the acceptance of some form of metaphysical higher power. Just to make sure we’re not talking about the same thing, but using different words for it.
I’d say that, pretty much by definition, there is an objective truth. The question is whether or not we can ever have access to that truth. If there are no deities, we may never be able to say with absolute certainty that we know that there are not deities, even if our certainty approaches 100%.
I disagree with your definitions of agnosticism and atheism. In particular, saying that atheism is “renouncing the existence of God” may carry the implication that something exists to be renounced or that God existing is the default position. It also implies that God is the only deity whose existence is under discussion, even though atheists do not have belief in any sort of deity.