James Anderson’s Does Presuppositionalism Engage in Question Begging article HERE
The Gospel Coalition is running a series on methods in apologetics. The latest installment is “Questioning Presuppositionalism” by Dr. Paul Copan, who raises four criticisms of presuppositionalism, one of which is the old canard that presuppositionalists engage in fallacious circular reasoning. (I think all four are misguided in one way or another, but the other three will have to wait for now.) He writes:
First, it engages in question-begging — assuming what one wants to prove. It begins with the assumption that God exists, and then concludes that God exists. Such reasoning would get you an “F” in any logic class worthy of the name!
Dr. Copan is a gentleman and a scholar, so I’m sure he doesn’t realize quite how insulting this sounds to presuppositionalists! (For comparison, imagine someone claiming that evidentialists commit the fallacy of affirming the consequent because they use inductive inferences.) This criticism has been answered many times, so it’s disappointing to find it cropping up yet again (although perhaps presuppositionalists should take comfort from the fact that Dr. Copan doesn’t offer any new criticisms!). Even so, I’ll try to explain one more time why this complaint so badly misses the mark.
In his contributions to the book Four Views on Apologetics, Dr. Copan’s fellow apologist William Lane Craig notes that this is a common criticism of presuppositionalism:
As commonly understood, presuppositionalism is guilty of a logical howler: it commits the informal fallacy of petitio principii, or begging the question, for it advocates presupposing the truth of Christian theism in order to prove Christian theism.
However, Craig also recognizes that the criticism is fairly superficial:
If this were all presuppositionalism had to offer as an apologetic, it would be so ludicrous than no one would have taken it seriously. But at the heart of presuppositionalism lies an argument, often not clearly understood or articulated, which is very powerful. This is an epistemological transcendental argument.
It’s therefore all the more surprising to find him repeating the “begging the question” charge, for once one understands the nature of a transcendental argument it’s clear that no fallacy of petitio principii is being advocated or committed. A transcendental argument typically takes the following form:
(1) If X were not the case, Y would not be possible.
(2) Y is possible.
(3) Therefore, X is the case.
In the presuppositionalist’s argument, X is the existence of God and Y is rational thought. … So let’s assume that the following is a workable summary of TAG:
(1) If God did not exist, rational thought would not be possible.
(2) Rational thought is possible.
(3) Therefore, God exists.
One common criticism of TAG is that presuppositionalists haven’t adequately defended the first premise. However, that’s not Dr. Copan’s criticism. His charge is that presuppositionalism is guilty of “assuming what one wants to prove.” But how exactly does the argument above assume what it sets out to prove? How does it assume the existence of God in any rationally objectionable fashion?
The problem here is that Dr. Copan, like many critics of presuppositionalism (and even some of its would-be defenders), confuses a presupposition of an argument with a premise of an argument. There’s a significant sense in which the argument above does indeed presuppose the existence of God. For if the first premise is true, the existence of God is a necessary precondition of rational thought, and the possibility of rational thought is a presupposition of all argumentation, including TAG. So in an obvious sense, if TAG is sound then TAG presupposes the existence of God (and so does the cosmological argument, the teleological argument, the moral argument, and every other theistic argument). But this is not at all to imply that the existence of God functions as apremise in the argument. TAG doesn’t look remotely like this:
(P1) God exists.
(C) Therefore, God exists.
Nor does TAG employ any premises that trivially presuppose the existence of God (e.g., “God is all-knowing” or “God has spoken in the Bible”). So it’s hard to see exactly why Dr. Copan thinks that presuppositionalism flunks Logic 101. …