I think that is one of the most misunderstood aspects of Van Til's thought. It is very abstract and "deep" but I will attempt to explain it, much smarter people could do a better job, but I'll give it a shot. Imagine a beach, you see it and you experience it. Isn't it lovely? Now imagine you are not God so you can't see the beach, who could? But what you can see is a painting of the beach. Now you would know all sorts of things about the beach, but not the beach as someone who is there. So their would be a different quality of knowledge, neither being false, between both knowers. We have image knowledge and God has God knowledge. I hope that helps.