What can we know with certainty about God? Is he even knowable on an objective basis? I think the answer would have to be no, at least for the natural man. There are things that are ascertainable about God by the natural man, some reasonable suppositions can be made by the natural man, but knowing about God with any accuracy, and knowing him personally are impossible to natural man.
God has intervened in and interrupted the lives of natural men in the past, which resulted in them coming to know God. Apparently, natural man is not so bereft of what it takes so as to be totally incapable of "getting something" when spoken to or confronted by God. Abraham, who is the model for all the rest of us, certainly proves the point, as do Noah and Moses.
I don't see how we can with any verifiability know or understand how God's "brain" works. How he knows all that he knows or wills what comes to pass is beyond discovering: it's just a given, part of his nature we accept without having the capacity to understand it or plumb its depths. We can know what God tells us; really, that is all we can know about God. In that sense, his Word is sufficient to bring us into the knowledge of God, at least the knowledge he would like us to have.
What does his word say about what he knows? It tells us that God's knowledge is such that he is capable of knowing things that could have happened but did not (2 Kings 13:19, I Samuel 23:12, Matthew 11:21). It tells us that we are an open book to God: that our thoughts are our thoughts and not his (Jeremiah 7:31, Isaiah 55:8-9), and yet that he knows our thoughts before we think them (Psalm 139:1-6). The word says that God knows what he knows without reference to time. In short, if it can or will be known, or even could have been known, God knows it.
How can a human truly comprehend all this, or understand it sufficiently to say how it works? We're not God--we cannot do what he does nor understand what he understands. We do have his word, however, and it tells us what we can and need to know about him. We may not be able to put all the pieces of the God puzzle together, but the word is sufficient to describe all that we can know about his omniscience.
