One of the most important aspects of any aspect of Christianity is that it is itself a complete system. Try to isolate any one component from the system and the same is no longer consistent. We see good example of this expounded by Greg Bahnsen in his book on Van Til’s apologetic in regards to B.B.Warfields method of apologetics:
“We thus see two things about the philosophical (epistomological) perspective which Warfield encouraged the apologist to take: it should be (1) outside of a commitment to Scripture and (2) in agreement with the right reason of the unbeliever-in a word, autonomous.”
Here we see two grave mistakes; one in that God’s authoritative word is not relevant at the outset of our dialogue with the unbeliever and two that Scriptures themselves must bow down to the rationality of the unbeliever before they can be accepted. So right out of the gate the Christian apologist who takes this approach is already defeated since the whold foundation for which he/she stands (The Holy Scriptures) is removed as a foundational basis for the apologetic and therefore it’s just a matter of whose rationality is more convincing.
I hope you can see another danger in this approach and that this approach is reduced to mere opinion and probability among may ideas. Of course this will fail from a pure reasoning standpoint with the unbeliever, because the unbeliever has become vain in his reasoning (Romans 1:21), and he cannot receive the things of the Spirit, because they are foolishness. (I Cor 2:14)
Let us remember that apologetics just like theology, evanlgelism, and philosophy are all part of a single system derived from the single authoratitive source of God’s Word.
Source of Quote: Van Til’s Apologetic – Greg Bahnsen