The difference between a Christian system that seeks to be consistently analogical and one, like that of Romanism and evangelicalism, that does not, is that only in the former is the false ideal of knowledge of the unbeliever rejected. If one does not make human knowledge wholly dependent upon the original self-knowledge and consequent revelation of God to man, then man will have to seek knowledge within himself as the final reference point. Then he will have to seek an exhaustive understanding of reality. Then he will have to hold that if he cannot attain to such an exhaustive understanding of reality, he has no true knowledge of anything at all. Either man must then know everything or he knows nothing. This is the dilemma that confronts every form of non-Christian epistemology. The Romanist or evangelical type of argument for Christianity is not able to indicate this fact with clarity. The only way by which this dilemma can be indicated clearly is by making plain that the final reference point in predication is God as the self-sufficient One.
– Cornelius Van Til, A Christian Theory of Knowledge p.17