How then we ask is the Christian to challenge this non-Christian approach to the interpretation of human experience? He can do so only if he shows that man must presuppose God as the final reference point in predication. Otherwise, he would destroy experience itself. He can do so only if he shows the non-Christian that even in his virtual negation of God, he is still really presupposing God. He can do so only if he shows the non-Christian that he cannot deny God unless he first affirm him, and that his own approach throughout its history has been shown to be destructive of human experience itself.
– Cornelius Van Til, A Christian Theory of Knowledge p.13