“Where then is the point of contact to be found? Where Paul says it is to be found, namely, in the fact that all men are created in the image of God. Man may try as he will, but he cannot eradicate this fact or his consciousness of it. His self-consciousness is a creature-consciousness. The prodigal son may always and everywhere act as though he had no father from whom his “substance” comes. Yet he knows he is a “liar” all the time.
So Paul says that, knowing God (gnontes ton theon), man wants to hold this knowledge under.
Here, and here alone, is contact in the mind and heart of the natural man for the gospel. The structure of reality as a whole is what Scripture says it is. Man is bound to carry on his interpretation within this structure. The non-believer must be presented positively with the claims of God in Christ for his conversion. This conversion must be a conversion of the whole man. He must learn to see that the reason why any man can think or do anything with respect to anything intelligently and with the proper Spiritual attitude is because by Christ’s atoning death and the Holy Spirit’s regenerating power he sees and does all things in a wholly different light, to the praise of his Creator-redeemer.
Then if the natural man continues to hold to his own position he is thereby shown that he does so because of his existential antagonism to the truth. He is adding sin upon sin in refusing to submit his thought captive to the obedience of Christ. If he continues in his false view of himself and his world this is, in the last analysis, because God has left him in his sin.”
(Van Til, A Survey of Christian Epistemology, 92-93)