The unbeliever is the man with yellow glasses on his face. He sees himself and his world through these glasses. He cannot remove them. His interpretation of himself and of every fact in the universe relating to himself is, unavoidably, a false interpretation. The conclusion that he, quite logically, draws from his assumption of his own autonomy is that the Christian position with respect to the creation, fall and redemption of man is the projection of a man who has illusions. There simply cannot be any such thing as creation. There can be no judgment after death. There can be no eternal punishment for sinners. There are no sinners.

It is therefore the idea of a common ground of interpretation that the “presuppositionalist” rejects. Such a common ground would be a meaningless monstrosity. Can any one intelligently assume that he is both a creature and not a creature, a sinner and not a sinner? Can any one intelligibly assume, with Hamilton, the Reformed theologian, that God is the source of possibility and with Hamilton, the apologist, that possibility is the source of God.

– Cornelius Van Til, A Christian Theory of Knowledge p.259