"I’ll conclude with a brief comment on the exceedingly low standard Bill [Craig] sets for a “good” philosophical argument. The premises don’t even need to be “plausible,” he says – “just more plausible than their opposites.” But surely, when you don’t know enough even to say, “This is plausible,” you don’t have a foundation on which to build an argument for a conclusion that you can believe! To see just how bad the problem is, suppose that each of the logically independent premises Bill needs to get all the way to the conclusion that a personal God created the universe meets this low standard. By way of illustration, suppose that there are just four logically independent premises, and make the very generous assumption that the probability is two to one in favor of each of them. Then the probability that all of them are true is less than 0.2, and the probability that at least one of them is false is greater than 0.8! Imagine a ladder with four rungs, and suppose that the probability that at least one of them will break is in the neighborhood of 0.8. Would you trust that ladder? No? Then you shouldn’t put too awfully much weight on this version of the cosmological argument!"
-Wes Morriston (from his opening statement in is dialogue with William Lane Craig)
Wes's comments on the dialogue with Craig can be found here.
4 comments:
I've also thought that Craig's standard for the acceptance of premises to be problematic because it looks like it runs straight into a Sorites sequence. Consider a pile of 1001 grains of sand, then construct an argument with 1000 premises of the form, "If X grains of sand is a pile, then X-1 grains of sand is a pile," yielding the conclusion that 1 grain of sand is a pile. Each premise is more plausible than not, but the conclusion is obviously absurd. If we applied Craig's criterion, then it looks like we should just accept the conclusion of the argument, in spite of it's obvious absurdity. I think you've previously defended the notion of taking disjunctive positions when disputing the premises of an argument, and I think such an approach is quite right and harmonizes with Morriston's point well and avoids this sort of Soritical concern.
Ironically, the youtube community was hammering Craig on this about a year ago. They're surprisingly good about this sort of thing, if you know where to look.
Craig responded with a lengthy website post that probably dropped his Evangelical college student reader's grades in philosophy by at least two letters.
He argued that one cannot assign numbers to these sorts of statements of probability. Instead, you can just use vague statements like "more plausible than their opposite." But of course anyone with the most basic of mathematical literacy can recognize that as a red herring argument. The mathematical relationship between the probabilities of your premises and the probability of your conclusions holds true even if you refuse to assign numerical values.
He also argued that anyone who contradicted him on these points was denying the validity of all deductive reasoning. He essentially used a radical skepticism based argument to claim that if nothing is truly certain, then you must accept that deduction takes place with uncertain premises, or else you must reject all deductive reasoning. Again, it was a red herring, obviously.
And in the midst of all that he continued to maintain that if you have an argument where each premise is more plausible than its negation, and where the argument follows the forms of deductive reasoning, then it is "irrational" not to believe the conclusions of the argument.
Reading this post was the point where I started actively disrespecting him. Before I didn't have any particular like or dislike for him, but after that post, dozens of religious kids swarmed the youtube channels that started the debate, all convinced that deductive logic worked the way Craig said it did.
Craig took the opportunity to use his soapbox to actively and intentionally make people dumber.
Craig's reply would be along these lines: http://www.reasonablefaith.org/site/News2?page=NewsArticle&id=8273
Thanks for the pointer, you two. I'll give it a look.
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