“Before moving to our next response against the anti-metaphysical bias, you should be aware of a possible response that the unbeliever will bring against you. He will complain that you are engaging in circular reasoning or the informal fallacy of begging the question. That is, since we assert that God is self-verifying, we are assuming God in order to prove God. However, we should note in response to this objection:
(1) We are not engaged in special pleading for the Christian worldview. We are simply asking which system makes human experience intelligible. For sake of argument, we will grant the unbeliever his system with whatever foundations he adopts in order to see if it can justify its own truth claims. But then he will have to grant us ours (for sake of argument) to see if we can justify our truth claims. By the very nature of our God as the self-existing, eternal Creator, our worldview self-justifies its starting point.
(2) All systems must ultimately involve some circularity in reasoning. For instance, when you argue for the legitimacy of the laws of logic, you must employ the laws of logic. How else can you justify laws of logic? This is a transcendental issue, an issue that lies outside of the temporal, changing realm of sense experience. Laws of logic do not change: they are universal, invariant, abstract principles.
In the Christian worldview, however, the Christian apologetic is not engaged in viciously circular argument, a circular argument on the same plane. We appeal above and beyond the temporal realm. God’s self-revelation in nature and in Scripture informs us of the two-level universe: God is not a fact like other facts in the world. He is the Creator and Establisher of all else. His existence alone makes the universe, reason, and human experience possible.
(3) “Circularity” in one’s philosophical system is just another name for ‘consistency’ in outlook throughout one’s system. That is, one’s starting point and final conclusion cohere with each other. Here it is more fully explained:
The ‘circularity’ of a transcendental argument is not at all the same as the fallacious ‘circularity’ of an argument in which the conclusion is a restatement (in one form or another) of one of its premises. Rather, it is the circularity involved in a coherent theory (where all the parts are consistent with or assume each other) and which is required when one reasons about a precondition for reasoning, its “circles” are destructive of human thought – i.e., “vicious” and “futile endeavors.
(4) The unbeliever has no defensible standard whereby he can judge the Christian position. His argument either ends up in infinite regress (making it impossible to prove), has no justification (rendering it subjective), or engages in an unjustifiable same-plane circularity (causing it to be fallacious). Without a self-verifying standard, he has no epistemological way out. And only the Christian worldview has such a self-verifying standard.”
(Bahnsen, Pushing the Antithesis, 123-125)