Predication is meaningless except upon the presupposition of the truth of Christianity. The unbeliever can intellectually understand this. It is the task of the Christian apologist to present the absolute contrast between predication carried forth upon Christian premises and predication carried forth on the premise of human autonomy. Roman Catholicism and Arminianism fail to present men with the full significance of the gospel because they do not challenge the starting point and the methodology of the unbeliever. Those who hold the Reformed Faith in theology can be of inestimable blessing to the unbeliever if, instead of following the Romanist and the Arminian, they apply the principles of their theology to the method of their apologetics.
– Cornelius Van Til, A Christian Theory of Knowledge p.272