Joe Carter at Evangelical Outpost has jumped into the Leiter/VanDyke fray, in a post filled with misconceptions and illogical statements. He begins:
For a legal scholar and professor of philosophy, Brian Leiter has a remarkably poor grasp of basic logic. For the past week Leiter has been bashing a defender of Intelligent Design theory using his typical rhetorical style of bullying and bluster. Instead of thinking up creative new ad hominem attacks, though, he should be paying closer attention to his reasoning.
At the risk of being pedantic, I have to point out this very common mistake in claiming the ad hominem logical fallacy. An ad hominem, contrary to how seemingly everyone conceives of it, is not merely an insult. Calling someone a jerk is not an ad hominem. An ad hominem is a logical fallacy, so there must be a mistake in reasoning in the formulation. The logical fallacy in an ad hominem attack is in responding to a substantive claim by referring to an irrelevant personal trait of the person making the argument. For example, if I said, “Joe Carter shouldn’t be listened to when he talks about ad hominems, look at the way he dresses”, that would be an ad hominem. I would be rejecting his arguments based upon an irrelevant personal trait. While Leiter is often rude and harsh in his attacks on people, those are not ad hominems. They may be insulting, but that doesn’t make it ad hominem.
Joe quotes this passage from Brian:
The difficulty, however, is that science did not “a priori pick a naturalistic methodology”; it adopted, based on evidence and experience (i.e., a posteriori), the methods that worked: it turns out that if you make predictions, test the predictions against experience, refine the hypotheses on which the predictions are based, test them again, and so on, you figure out how to predict and control the world around you. This is what the Scientific Revolution, the Enlightenment, and a few other ancient events apparently not covered in Mr. VanDyke’s education, were about: the a posteriori discovery of the most effective ways to predict and control the world. This, of course, distinguishes the naturalistic worldview of science from the supernatural view of religion, which is genuinely a priori.
And begins his response:
There are numerous problems with Leiter’s reasoning but I will point out just three. The first is that his methodology would lead to conclusions that Leiter himself woudl presumably reject. Take for example the “anthropic principle.” We could predict, post hoc, what type of universe would be required to produce human life, but we’d be unable to test the theory (we aren’t able to repeat the Big Bang).
Does Joe really think that if we can’t repeat an event, we can’t test explanations for that event? This would rule out whole fields of science, including the one he mentioned. Big bang cosmology is entirely testable, and has been tested, without having to repeat the big bang itself. Testability requires making predictions about the nature of new evidence, not repeating the event itself. It would also, by the way, rule out the entire field of forensic science, which is used to convict people and even put them to death on a daily basis in this country. By Joe’s reasoning, you would have to actually recreate the murder in order to test forensic explanations for the murder. But that’s not how it’s done, of course. You test the forensic explanation by making predictions. If the bullet came from gun X, then we make predictions Y and Z. If Y and Z are confirmed, the explanation is validated.
We could, however, determine the likelihood that the event could have occurred by pure chance. Since the probability of such a series of events occurring by coincidence would be close to zero, we would be lead, by evidence and experience, to the conclusion that the universe was “designed.” (To conclude otherwise would require taking an a priori prejudice against supernaturalism.)
I’ll take issue with Joe’s claim that we can determine the likelihood of the big bang, or the so-called anthropic coincidences, occuring by “pure chance”, and I’ll challenge him to produce such a calculation. We hear this argument over and over again, but it’s never accompanied by an actual probability equation. If you think we can calculate the probability of either of those two things, let’s see the probability equation.
It should also be noted here that even if such a probability equation were possible, it wouldn’t tell us anything meaningful about whether the event could have occured naturally or supernaturally. The perfect illustration of this is Marshall Berman’s example of the rock in the backyard:
Go outside and pick up a small rock. The probability of that rock being on that spot on the earth *by chance alone* is roughly the area of the stone divided by the surface area of the earth, or about one chance in 10 to the 18th power (one followed by 18 zeros). If picking up the stone took one second, the probability of such an event occurring at this precise moment over the lifetime of the universe is now even smaller by another factor 10 to the 18th power! This simple event is so incredibly unlikely (essentially zero probability) that one wonders how it could be accomplished!
The second reason is that the “what works” approach gives us no reason to believe that our conclusions are true. I may believe, for example, that my dryer contains a black hole that causes socks to disappear. Every time I put a load of clothes in the machine I find that I’m missing a sock. The more I repeat this experiment the more socks I lose, thereby providing sufficient evidence to confirm my theory.
Joe seems to be confusing facts with explanations. Socks disappearing from your dryer would be a fact; the “black hole hypothesis” would be a potential explanation for that fact to be tested. The continued occurence of the fact does not test the potential explanation. Doing laundry would not constitute “repeating the experiment”, since doing laundry does not test the explanation at all. In other words, this is an absolutely absurd analogy for how science tests a hypothesis.
The black hole hypothesis could of course be tested in other ways, as black holes have predictable effects. If there was a black hole in your dryer, it would have a quite noticable effect on gravitational pull around the dryer. It would also not be able to distinguish between socks and other types of clothing, since black holes are not conscious entities and would simply obey the laws of physics. Now, Joe might invoke a violation of the laws of physics here and say that this is a magic black hole that only makes socks disappear and doesn’t have any other predictable effects. But in doing so, Joe would demostrate for us exactly why science rules out supernatural explanations, because once you allow them, all bets are off – there is absolutely no way to discern true supernatural explanations from false ones. Can you propose a means of distinguishing the “magic black hole” hypothesis from the “malevolent demons” hypothesis or the “mischievous leprauchans” hypothesis? Of course not. In other words, Joe’s analogy is a really good argument against his thesis.
Leiter, of course, would claim that we should use Occam’s razor and exclude the necessity of the black hole to explain the missing socks. But this would require us to take an a priori position in favor of the principle of parsimony in order to preserve methodological naturalism. My theory would work well enough that I would have no reason to test it further and while it might not be “true”, the a posteriori examination of the evidence makes it a plausible explanation. After all, naturalistic methodology doesn’t require us to take a priori assumptions about truth.
Leiter would not have to invoke Occam’s Razor to distinguish between two explanations here, because Joe’s hypothetical explanation hasn’t been tested at all, and if it was tested by making predictions about the effects of a black hole, it would be falsified. Joe is pretending that he has two equally plausible explanations that explain the exact same things equally well, when in fact he doesn’t have such an explanation at all. He has one very bad analogy that, if made more analogous, would fail miserably as a theory.
The third reason Leiter’s argument fails is that he has no justification for excluding other theories or methods that don’t rely on methodological naturalism. Just because a method works doesn’t mean it is infallible. The method provided us with Newtonian physics, a hypothesis that “worked” well enough…until it didn’t. Do we regard the theory as having always been an implausible scientific hypothesis just because it was replaced by another? Of course not. The same applies to methods. Just because methodological naturalism “works” (at least sometimes) does not mean that it is the only valid method or that it cannot be replaced. Besides, you can’t (without resorting to an a priori assumption) exclude other methods as invalid without allowing them to be tested.
This would be a serious objection if, and only if, there was some means of testing those “other methods”, in this case the ID explanation. And if Joe can come up with a testable hypothesis that flows from ID, or a way to falsify ID, he’ll be the first to do it.
Leiter’s reasoning shows that his bias against intelligent design theory is not rooted in science but in prejudice. By acknowledging that science does not require an a priori submission to naturalism he inadvertenly undercuts his own argument. He can’t claim that methodological naturalism is the “most effective ways to predict and control the world” while refusing to allow other methods to be tested.
Again, Leiter is not ruling out ID without allowing it to be tested. He’s challenging the ID advocates to put forth a real model with testable hypotheses that flow logically from it and propose a means of testing those hypotheses. But they haven’t done that, and I don’t think they can. It’s not by accident that all of their publishing efforts to this point have been trying to poke holes in evolution. The entire ID argument up to this point comes down to one big God of the Gaps argument – “Evolution can’t explain X, therefore God (sorry, the unnamed – wink, wink – intelligent designer that we know nothing about) must have done it”. There are no testable hypotheses that flow from that. So it simply isn’t a question of anyone “ruling out” ID without testing it, it’s a question of there not being any means of testing it. And if the ID advocates think that’s false, all they have to do is actually publish some means of doing so, as we have been challenging them to do since at least 1997′s NTSE conference. That deafening silence you’ve been hearing in that regard is quite telling, don’t you think?