The philosopher Thomas Nagel wrote a famous essay where he pointed out – in my opinion, correctly – that it is impossible for a human to know what it’s like to be a bat. We can know every mechanical detail of a bat’s anatomy and get detailed descriptions of what it perhaps might be like if we were a bat, but the actual experience of being a bat is something that will forever elude us.
You might call this a limit on the omniscience of God; if omniscience is knowledge of all things possible to know, then “What it’s like to be a human” is something impossible for God to know, because God is, by definition, not human. He’s God. He can be intimate with all of the knowledge of every human alive, but God cannot know what it’s like to be a human.
Or so we’d think. What if that wasn’t true? What if God decided to become a human himself? Is such a thing possible?
It seems like a contradiction, but then we need to explain the historical record: It actually happened, and it was witnessed and recorded. God Himself, the God of the philosophers, somehow took on human flesh, lived a human life, and died a human death. The great gap was bridged; God could understand intimately, perfectly, with direct firsthand knowledge, EXACTLY what it’s like to be a human.
Nothing like this had ever been even conceived of happening before. Sometimes humans – like Dionysius – were raised up to the level of the divine, but no myths and legends ever recorded divinity turning Himself into a man. It’s a preposterous idea; what value could there possibly be?
In fact, there is only value in it if God Himself valued having a full and intimate knowledge of what it was like to be a human; if God so loved the world that He was willing to suffer and die the death of the slave so he could experience the world in full, its triumphs and sorrows, in a way He could not if he remained pure Spirit.
This, then, is the Incarnation. It is God filling in the one significant gap of the divine knowledge, because he loved mankind so much He could not bear not knowing.