To be honest, since atheists on the internet (also in philosophy, IMO) tend to tout some very bad criticisms of theism, I wasn't holding my breath in this case. However I was extremely and pleasantly surprised at what I heard! I must say, the folks at Reasonable Doubts really came through. Although there are spots where I have minor quibbles, in sum they present quite nicely the presuppositionalist case, and zoom in on two of its most serious and immediate problems. In addition, the tone of the podcasts are humorous and friendly, and in each case makes for an extremely entertaining listen. I highly recommend them!
Recall that the general strategy of Van Tilian presuppositionalists is to raise a philosophical problem which they claim is unique to non-Christians, and complain that it is only solvable with Christian presuppositions. (This one-sentence summary of presuppositionalism will have to do for our purposes here.)
The folks at Reasonable Doubts identify two key flaws in this strategy: First, quoting Gene Witmer's lamentably little-known talk on the subject, they point out that presuppositionalists simply presuppose their most basic religious views, and that if this is an appropriate move for the presuppositionalist then the non-presuppositionalist can do the same with the philosophical positions, only without also presupposing anything religious. I would add that far from being a mere hypothetical exercise, indeed this is exactly what we should do in most contexts, as long as we're honest and humble about what we're doing. Second, presuppositionalists do not, in fact, offer any solution to the philosophical problems which they claim plague unbelievers. Rather, we're all in exactly the same proverbial boat, and no appeal to God has yet changed that. So their criticisms, to the extent we might want to take them as being effective, apply to themselves as much as unbelievers.
In addition to these two observations mentioned by the Reasonable Doubtcasters, I also like to stress a third important criticisms of Van Tilian presuppositionalism, which is that they often don't offer any valid or cogent argument for their central views, namely the truth of Christianity or the existence of God, instead relying on a rhetorical strategy for use in debates, dialogs, etc., aimed at making non-presuppositionalism look silly. You won't find, for instance, any clear-cut argument in Greg Bahnsen's debate with Gordon Stein. Instead he talks around his supposed argument, referring to it from time to time without actually stating it in clear terms. Especially consider the last segment of Bahnsen's opening statement:
When we go to look at the different world views that atheists and theists have, I suggest we can prove the existence of God from the impossibility of the contrary. The transcendental proof for God's existence is that without Him it is impossible to prove anything. The atheist world view is irrational and cannot consistently provide the preconditions of intelligible experience, science, logic, or morality. The atheist world view cannot allow for laws of logic, the uniformity of nature, the ability for the mind to understand the world, and moral absolutes. In that sense the atheist world view cannot account for our debate tonight.
Certainly that paragraph itself does not contain any argument for the existence of God, much less Christianity as a whole. Instead, Bahnsen devoted his opening statement to criticizing Stein's particular anti-religious views. So even if his critique was entirely justified (which is hardly the case, but let's assume for the sake of argument that Bahnsen was uniformly correct in that regard), it would not follow that Christianity is the one true religion, nor would even just the more modest claim that God exists. All Bahnsen did in his debate was employ the same strategy of criticism and ridicule of particular non-presuppositionalist positions.
This is a typical example of Van Tilian presuppositionalism in action. A similar example can be found in my debate with Jamin Hubner (I recommend the transcript of this rather than the audio, since I'm not really a great speaker).
On the other hand, some Van Tilians genuinely attempt to construct actual arguments for their beliefs. Sometimes these depart from the strategy mentioned above, as was the case for example in the recent paper "Lord of Non-Contradiction" by James Anderson and Greg Welty (2011, Philosophia Christi), and hence require their own responses. (However such arguments, to the extent that they depart from the Van Tilian strategy, cannot rightly be called Van Tilian.) In other cases the argument reflects a deeply Van Tilian apologetic, e.g. in my debate with Chris Bolt (again, I recommend the transcript over the audio), or Don Collett's brief argument based on Bas Van Fraassen's supervaluations.
Anyway, I was very pleased in all with the Reasonable Doubtcasters these past couple of weeks. Go check them out!
Also, feel free to read/listen to some of my own critiques of Van Tilian presuppositionalism in the links below:
Goodness Over God podcast with guests Sye Ten Bruggencate and Pastor Dustin Segers
more on Pastor Segers' argument
more on Sye Ten Bruggencate's criticisms
Goodness Over God podcast with guest Brian Knapp
Brian Knapp and the atheist's burden of proof
more on the atheist's burden of proof
response to Don Collett's argument
my debate with Jamin Hubner (I recommend the transcript rather than the audio)
my debate with Chris Bolt (I recommend the transcript rather than the audio)
more on my debate with Chris Bolt
inductive standards (last response to Chris Bolt)