A question from Open Theism:

This is why I feel as though if anybody is to be a philosophically reasonable theist, they must be an open theist. Of course there is the issue of verses such as Psalm 139:4, and so on.

John McCormick replies:

Psalms 139:4 MKJV
(4) For there is not a word in my tongue, but, lo, O Jehovah, You know it altogether.

Let’s say that this is literal, even though the genre is poetic.

God certainly knows what is going on in our lives. He surely knows the signals passing through our nervous systems and our brains (though not our souls). He knows which things in our environments affect us and He knows how we normally talk, our speech patterns.

My wife and I say the exact same thing a frighteningly large amount of the time. We plainly connect on some level, either subconsciously through body language and other signals or through some “telepathy” as yet unrecognized by science.

If WE can communicate that well, it has to be a simple thing for God to know what we will say at least somewhat ahead of time.

However, I suspect that David was exaggerating poetically. The passage shows David’s surprise that God knows what he is going to say.

But the passage doesn’t specify the limits of God’s knowledge of what David is going to say. It doesn’t specify whether David means “from the beginning of my life to the end” or “all in this conversation I’m having with Him” or somewhere in between.

The sense in Psalm 139 seems to be that God knows David intimately, in a personal sense, not that David is explaining some technical description of God’s knowledge. Verse 3 says that God is “acquainted with all [of David’s] ways”, which suggests that God has learned about David rather than simply knowing automatically.