“Presuppositional Procedure” by Greg L. Bahnsen
Here then is how the presuppositional (transcendental) method of defending the faith would proceed once the preliminary discussions and clarifications have taken place with the unbeliever – and the two outlooks now come head to head. The unbeliever says that he knows that miracles are impossible, that a personal almighty God does not exist, that ethical principles are not normative across cultural boundaries, etc. Or the unbeliever says that the believer cannot know that the Bible is God’s word, or that Jehovah exists, or that Christ was His Son, etc. The Christian apologist must seek to uncover what this unbeliever’s personal convictions are regarding metaphysical and (coordinated with it) epistemological matters which are relevant: e.g., what is the nature of things which are real, how does the world operate, where did it come from, what is man’s place in the world, what is man’s nature, are there moral or epistemological norms which are not chosen by the individual, what are the criteria of truth, what are the proper methods of knowing, is certainty possible, etc.? Once the believer has a fairly good grasp of the general kind of worldview assumed (or explicitly advocated) by the unbeliever, we can suggest that it should be compared to the worldview of the Christian. The Christian can show that the particular objections raised by the unbeliever would, within the Christian outlook, not prove to be legitimate objections or intellectual problems at all. Thus who really “knows” what he is talking about, the Christian or the non-Christian? The cogency of each side’s theory and practice of knowing must be tested within the broader worldviews of which they are a part. The apologist explains how rationality, communication, meaning, science, morality, man’s redemption and renewal are quite understandable, meaningful, coherent, or intelligible within the Biblical worldview – within “the picture” of thinking God’s thoughts after Him. The apologist then engages in an internal critique of the unbeliever’s worldview to show that it is (1) arbitrary, and/or (2) inconsistent with itself, and/or (3) lacking the preconditions for the intelligibility of knowledge (language, logic, science, morality, redemption, etc.). Since that is the case, the unbeliever cannot “know” the things which he urges against Christianity – indeed, could not know anything at all and loses all claim to rationality. The Christian has proven the rationality and necessity of His scripturally based worldview. …