It is utterly impossible that there should be trustworthy witnesses to the incarnate Word unless these trustworthy witnesses are trustworthy because they are the servants of the self-attesting God, speaking through the Son of God. This is only to say that any identification of any fact can take place in terms of the truth of the Christian religion alone. It is but to say that Christianity alone is rational. It is but to say that if one leaves the foundation of the presupposition of the truth of the Christian religion one falls into the quagmire of the utterly irrational. No intelligent predication is possible except on the basis of the truth, that is the absolute truth of Christianity.
– Cornelius Van Til, A Christian Theory of Knowledge p.252