Agnosticism is epistemologically self-contradictory on its own assumptions because its claim to make no assertion about ultimate reality rests upon a most comprehensive assertion about ultimate reality.
Cornelius Van TilI shall not convert you at the end of my argument. I think the argument is sound. I hold that belief in God is not merely as reasonable as other belief, or even a little or infinitely more probably true than other belief; I hold rather that unless you believe in God you can logically believe in nothing else.
Cornelius Van TilSo, as we have our tea, I propose not only to operate on your heart so as to change your will, but also on your eyes so as to change your outlook. But wait a minute. No, I do not propose to operate at all. I myself cannot do anything of the sort. I am just mildly suggesting that you are perhaps dead, and perhaps blind, leaving you to think the matter over for yourself. If an operation is to be performed it must be performed by God Himself.
Cornelius Van TilTo admit one's own presuppositions and to point out the presuppositions of others is therefore to maintain that all reasoning is, in the nature of the case, circular reasoning. The starting-point, the method, and the conclusion are always involved in one another.
Cornelius Van TilThe only proof for the existence of God is that without God you couldn't prove anything.
Cornelius Van TilIf 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. 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
Cornelius Van Til