First, the atheistic humanist claims to know enough to say that God does not exist. This is a claim to know everything, for if he admits that he does not know everything, how does he know that God is not included in what he does not know? Secondly, the agnostic humanist thinks to avoid the problem of this atheist by saying that we cannot know if God exists or not; he may or he may not. But this is also to claim exhaustive knowledge, for how can he know that God’s existence cannot be known other than by knowing everything there is to be known? The last thing left for him to discover may be the evidence that God either exists or does not exist. Finally, the Christian knows that he does not have exhaustive knowledge. But he knows also through revelation that God does have exhaustive knowledge and can therefore define for us what reality is. By the same revelation this God has told us all that we need to know in order to know truly. The Christian can know God truly. He can know man truly, and the created order truly. He knows none of them exhaustively, but he does know them truly.
(Graeme Goldsworthy, Gospel and Wisdom, emphasis added)