I was first introduced to presuppositional apologetics through an online forum where several older, wiser, and honorable Reformed men handed me my hat in several arguments, many of them unrelated to apologetics. As my respect for these men grew, I sought them out for things to read to grow my feeble understanding of theology, and to sharpen my own thinking in general. Three names were mentioned most; Gordon Clark, Greg Bahnsen, and R. J. Rushdoony. The former two were trained philosophers and wrote positive contributions to Christian theology and apologetics as well as defended Christianity against opposing claims. The latter wrote more widely, and (to my knowledge) did not deal specifically with apologetic method in his writings as did Clark and Bahnsen. I've always found these authors to be lucid and compelling, disagreeing with them only on minor points for the most part.
However, I have often encountered folks who find Clark and Bahnsen to be rather unconvincing and underdeveloped in their claims, providing more assertions than arguments. In fact, a friend of mine whose opinion I take seriously commented that he found Bahnsen's "Great Debate" with Gordon Stein to be terrible, mostly because Bahnsen was short on argument and long on assertion. He cited Kelly James Clark, an apologist of the Reformed Epistemology stripe, who made a similar remark about the debate in his response to John Frame's presuppositional position in the Five Views on Apologetics book. Prior to this friend's comments, I had once shown my graduate professor (who was usually pretty even-handed in evaluating arguments) a criticism of Marx, written by Clark, and the professor thought it was an absurd representation of Marx's viewpoint. Finally, in the online forum where I had first encountered these authors, many folks found presuppositional arguments and their proponents to be not only unpersuasive, but something akin to purveyors of cheap parlor tricks--a sort of Christian sophistry, if you will.
While I respectfully disagree with all of these criticisms, I have tried to come up with some plausible reasons why a method I find to be so cogent and pristine in its argument is considered so banal and reprehensible to others. Here's what I've come up with so far:
1. "Presuppositionalism isn't very persuasive to unbelievers, in fact, it doesn't seem to even try to persuade." There is some merit to this criticism, in the sense that presuppositionalism acknowledges that persuading unbelievers to accept Christianity isn't the primary goal of its apologetic. Presuppositionalism is essentially destructive in nature; it seeks to tear down alternatives to Christianity in order to leave the unbeliever "without excuse," or as Bahnsen might say it, to leave the unbeliever in direct confrontation with his own self-deception. Given this negative approach, there is usually less argument devoted to proving positive claims about Christianity. Evidences are not rejected, but neither are they frequently appealed to for support. They are seen as secondary to the destruction of foundational assumptions the inhibit opponents from rightly interpreting evidences, yes, even from accepting evidence as valid. To some this approach seems disingenuous, even unsupportable--isn't one obligated to provide positive arguments for one's own position? However, one must recognize that, with regard to knowing the truth, knowing what is false is also useful. Indeed, knowing something as false entails knowing its contrary, the truth of which is logically entailed. Therefore the presuppositionalist usually only advances one positive claim, the transcendental proof of God's existence, which claims that Christianity is true by the impossibility of the contrary. The apologist then spends the entire debate showing how something that his opponent considers indispensable to his own position is only rationally supportable upon Christian presuppositions. It is a positive argument through negative means. It seems sneaky, but it is just indirect. You can catch a bear by coming at him head-on with a large net, or you can put some fish in a cage with a trap-door.
2. "Presuppositionalism doesn't respond directly to opponents' claims, but just accuses them of being irrational, inconsistent, arbitrary, or incompatible with human experience." Like the first objection, there is some superficial merit to this claim. Presuppositionalism is, by design, an indirect critique of opposing positions. It seeks to provisionally accept the claims of the position it seeks to refute, and then show that contradictions, arbitrary standards, or incompatibilities are logically entailed by its foundational assumptions. Thus, if an empiricist were to say, for example, "How can you, as a Bible-believing Christian, accept that the sun stood still as it is stated in the book of Joshua, when scientifically such an event would be catastrophic for the entire planet?" a presuppositionalist might respond by asking how the empiricist knows that the sun hasn't stopped right now, or how does he know that the sun's stopping now would result in catastrophe. Thus, instead of answering the question, the question is turned back on the opponent, forcing him to justify the grounds of his own objection. The presuppositionalist simply asks, "Can the empiricist's objection stand upon the foundation which the empirist has used to support it?" If it cannot, the force of the objection disappears. While this seems unfair or disingenuous, it is not underhanded at all. Suppose someone accused you of stealing and demanded that you prove your innocence. Would it be unfair for you to ask what grounds the accuser has for his claim that you have stolen? So while an indirect method may be quite unorthodox in terms of how most debates proceed, it is not thereby unfair, disingenuous, or otherwise evasive or unethical. Indeed, the naturalist could with good will and good reason ask the Christian for the grounds of his objections to naturalism. Moreover, as I mentioned in the first objection, the presuppositionalist does use positive claims, but they are usually few and depend upon an indirect method.
3. "Presuppositionalism is a petitio principii, a circular argument fallacy that assumes its conclusion in order to prove its conclusion." There is a sense in which presuppositionalism is circular, however, presuppositionalism makes the claim that all systems of thought are self-referential and therefore circular, but not in a fallacious way. For example, the Christian by his very fact of being so, assumes that God exists--otherwise he would not be Christian. Similarly, the naturalist, by his own convictions, assumes that the world contains no spiritual realities--otherwise he would not be a naturalist. The Christian and the naturalist cannot cease to accept these assumptions without also ceasing to be what they are by conviction. The best either can do is to assume, for the sake of argument, that the opposite of what he believes to be true is true, and see where that would lead--which is precisely what the internal critique of presuppositionalism attempts to do. But even in the assumption of this "unbelief", one is only doing so hypothetically, for otherwise one's convictions would be changed and one would no longer be arguing against the view on behalf of his original position--his own view would have changed. The supposed neutrality of debate is really not neutrality at all, but rather a willingness to follow the logic where it leads whenever one's assumptions are made manifest. Further, the rational approach to being persuaded could only proceed through the destruction of one's accepted assumptions that prevent the change of mind!
4. "Presuppositionalists are only interested in winning the debate, and aren't concerned about presenting the best arguments." I suppose this claim could be true in many cases where presuppositionalists have debated, but I've never been shown how such a tendency is "built into" presuppositionalism--it isn't logically entailed. I think this objection is also related to the method of internal critique used by presuppositionalism. When the presuppositionalist consistently demands that his opponent offer justification for his claims and objections instead of responding to them directly, it can appear that the presuppositionalist is simply trying to "score points" or avoid the difficult arguments of his opponent. Of course, the presuppositionalist maintains that he is very much engaged in proving his case while also answering his opponent's case, but his indirect method of doing so often trips up the opponent and/or the audience because it looks a bit too much like Socrates' gadfly tactics of elenctic argumentation.
5. "Presuppositionalists come across as arrogant, as if they were the only ones with access to truth; that certainty is the only valuable kind of knowledge, thereby disdaining probable arguments." Presuppositionalists believe that God's Word declares knowledge of God to be basic to man, and that God's revealed truth in the Word is irrefutable. If man both knows God, and God's truth is irrefutable, then there is a real sense in which the Christian has "cornered the market on the truth," although the truth about God is possessed by all men in differing degrees. The problem of the unbeliever is not, therefore, predominantly intellectual--a problem of ignorance--but moral; he has only rejected Christianity out of rebellion and consequent self-deception. When ignorance is the problem, instruction in probabilities can be of some use. But when truth is being suppressed, there is little value in relying upon probabilities, since they always afford the possibility of legitimate denial. There is room to persist in rebellion and self-deception. Consider Paul's Areopagus speech in Athens--he does not seek to advance the probability of God's existence or Christ's resurrection. Instead he uses it as the basis of his criticisms of the Greeks' system of belief. One may object to using Paul as a good example of apologetic method, I suppose, but I'm not sure many Christians would take that line. Consider another analogy. If the King of the land sent a proclamation through his many heralds that he had conquered all of his enemies, and that anyone wishing to bow to the King's authority should make public confession and abide in the King's commands, would the heralds use probable arguments to support the fact that the King really had conquered his enemies, or that he really had given the proclamation? Would he not rather insist upon the certainty of the King's reign and rule, and emphasize the peril of those who would be skeptical? When claims of "maximal warrant" are available, why resort to arguments that have less warrant?
There are probably many other criticisms of presuppositionalism, and there are certainly more philosophically challenging critiques, but my main objective has been to address common objections that an audience or newcomer to the method might raise.