1. Is God knowable?
Yes. Scripture teaches this: “that we may know the One who is true” (1 John 5.20), although it also reminds us of the limited character of our knowledge (Matthew 11.25).
2. In what sense do Reformed theologians maintain that God cannot be known?
a) Insofar as we can have only an incomplete understanding of an infinite being. b) Insofar as we cannot give a definition of God but only a description.
3. On what grounds do others deny God’s knowability?
On the grounds that God is All-Being. They have a pantheistic view of God. Now, knowing presumes that the object known is not all there is, since it always remains distinct from the subject doing the knowing. Making God the object of knowledge, one reasons, is equivalent to saying that He is not all there is, that He is limited.
4. What response is to be made against this view?
a) The objection that this view presents stems entirely from a philosophical view of God, as if He were All-Being. This view is wrong. b) God is certainly infinite, but God is not the All. There are things that exist whose existence is not identical with God. c) It is certainly true that we cannot make a visual representation of God because He is a purely spiritual being. But we also cannot do that of our own soul. Yet, we believe that we know it. d) It is also true that we do not have an in-depth and comprehensive knowledge of God. All our knowledge, even with regard to created things, is in part. This is even truer of God. We only know Him insofar as He reveals Himself, that is, has turned His being outwardly for us. God alone possesses ideal knowledge of Himself and of the whole world, since He pervades everything with His omniscience. e) That we are able to know God truly rests on the fact that God has made us in His own image, thus an impression of Himself, albeit from a great distance. Because we ourselves are spirit, possess a mind, will, etc., we know what it means when, in His Word, God ascribes these things to Himself.
From: Reformed Dogmatics: Volume One: Theology Proper by Geerhardus Vos; translated from the Dutch supervised by Richard B. Gaffin, Jr. (Bellingham: Lexham Press, 2014), pp. 1-2.