If you were hanging around Stephen Law’s blog a few years back, you may remember a lengthy series of posts dealing with Sye Bruggencate (archived here at Skeptic Ink: 6, 5, 4, 3, 2, 1) and you may remember that Sye was completely unmoved no matter how carefully and thoroughly his arguments were taken apart. If you remember all this, it will come as no surprise now that Sye is still drawing from the same old bag of tricks:
I recommend watching at least the ten minute segment starting around 26:16 if you’d like to hear a really decent pre-scripted rebuttal to the typical presuppositional gibberish. Or watch to the whole thing, if you’ve got that sort of spare time. (Incidentally, the moderator is David Smalley of Dogma Debate, who was here in OKC just last week.)
One of the ways to approach presuppositionalism is to analyse its premises one by one as Professor Law did, or as Notung does here. Another way that I would like to suggest, if you happen to find yourself in an dialogue with someone who takes this particular and peculiar approach, is to start off by listing all the suppositions that you both need to make in order to have a meaningful discussion one with another, e.g. your mind exists, their mind exists, you are exchanging ideas using some particular language(s), you agree upon the meanings of key terms, you agree upon various entailment relations, which system of logic you are going to utilize to draw conclusions, etc. The list is longer than you might think, and usually includes loads of background assumptions such as the assumption that the real world exists, you are both observing it, and you are both in possession of sufficient background knowledge to understand each other.
Now that you’ve got a mutually agreeable list in front of you, ask yourselves whether it can somehow be improved by adding in the presupposition that the universe is presided over an immaterial megamind mediating by mysterious means. Of all the presumptions routinely made by any two persons attempting to reason together, which ones would be enhanced by adding in some sort of god hypothesis, and how?
I cannot tell you how such a dialogue will turn out for you, but I can guarantee that it will be more enjoyable and enlightening than talking to Sye himself.