In the first place it must be affirmed that a Protestant accepts Scripture to be that which Scripture itself says it is on its own authority. Scripture presents itself as being the only light in terms of which the truth about facts and their relations can be discovered. Perhaps the relationship of the sun to our earth and the objects that constitute it, may make this clear. We do not use candles, or electric lights in order to discover whether the light and the energy of the sun exist. The reverse is the case. We have light in candles and electric light bulbs because of the light and energy of the sun. So we cannot subject the authoritative pronouncements of Scripture about reality to the scrutiny of reason because it is reason itself that learns of its proper function from Scripture.
– Cornelius Van Til, The Defense of the Faith p.130