The way in which we reason, how we evaluate claims to the truth, the standards we adopt for knowing, etc.–is itself an ethical matter. …
A person cannot have it both ways regarding his final standard or ultimate reference point. He presupposes and reasons either according to the authority of God or according to some other authority. Attempting to be neutral about God’s ultimate authority in determining what we know is a result of a bad attitude toward God’s ultimate authority.
Greg Bahnsen, Van Til’s Apologetic, 90, 92