Wednesday, May 22, 2013

An exchange with Christian apologist Victor Reppert

I sometimes participate in the commentary on John Loftus's blog Debunking Christianity, and this affords me the opportunity to have discussions with some of the apologists that frequent it as well, attracted like moths to a flame, we might say. One such apologist that infrequently comments, at least since I've been following the blog, is Victor Reppert, who essentially follows in C.S. Lewis's line of thinking.

Loftus asked an open question on his blog a couple of days ago: "Question for Discussion: What evidence is there for Christianity?" (Link). Amid discussion about this or that in the Gospels or from the Epistles of Paul--which aren't exactly evidence, a point Loftus has been consistently and clearly able to defend for years--Reppert joined in to make a more sophisticated reply. Here it is, Reppert speaking in green:
Wouldn't it be an idea to come up with a concept of what we mean by evidence before we ask whether we have any? X is evidence for Y just in case Z?

To me, X is evidence for Y just in case X is more likely to exist if Y than if not-Y. But now, if we go with that definition, then the existence of reports that Jesus was resurrected from the dead is unlikely given the claim that Christianity is false. After all, most people do not have people claiming they were resurrected after they died. (Not even Elvis Presley, though there are people who claim he never actually died). But we should expect it to be reported if Christianity is true, so, in and of itself, the existence of resurrection claims on behalf of Jesus are evidence that Christianity is true. Plug it into Bayes' theorem and it ups the probability.

Now, you might say that that's crummy evidence, and in and of itself it surely wouldn't persuade much of anyone. But if you want to deny that it is evidence at all, you need to supplant my definition with one of your own.

I am willing to embrace the logical consequence that the testimony to the Golden Plates is evidence for Mormonism. But my view would be that the weight of the evidence is against Mormonism, not that there is absolutely no evidence at all for it. I've, for a long time, been asking for a definition of evidence that allows us to draw the conclusion that there is no evidence for Christianity, a claim I would NOT make even about such patently false claims as Mormonism, or even Scientology.
Okay, it would be nice to "come up" with a concept of evidence, but I would expect that the philosophy of science (and scientists) have this pretty well hashed out already. Perhaps, from Reppert's perspective, we still need to "come up" with one because it doesn't work for establishing that religions like Christianity are true?

In any case, I offered this reply, my interest piqued by his mention of Bayes's Theorem, upon which I've blogged before (which reminds me... I really need to write that piece about how the method I presented before, which I employed following Richard Carrier's use of the theorem, is not the best way to use Bayes's theorem):

That's evidence to add to the veracity of the resurrection using Bayes's theorem?

Only if you consider it against alternative hypotheses, for example--that people just make up stories about their hero figures. But you feel you've protected yourself from this by saying "most people do not have people claiming they were resurrected after they died." Hmm, don't need most. We only need big heroes, and really only need the death/rebirth theme.

Baal, Melqart, Adonis, Eshmun, Osiris, Dionysus, Tammuz, Ra, Ishtar, Persephone, Bari, Dumuzi, Asclepius, Achilles, Memnon, Alcmene, Castor, Heracles, Melicertes, Aristeas of Proconnesus, the boy raised by Elijah (1 Kings 17), the son of Shunammite woman raised by Elisha (2 Kings 4), body thrown into Elisha's tomb (2 Kings 13), and Lazarus, to limit ourselves to well-known ideas in the relevant region preceding the time of the writing of the gospels.

It's pretty hard to look at that list and think "people who wrote the bible would never have thought of that theme unless it really happened to Jesus." Contribution to Bayes's theorem? Not only would it be negligible if argued positive, it should be a hammer blow on the idea that such a story is "evidence" for the resurrection of Jesus, even by your odd definition.
Perhaps I should elaborate briefly upon why Bayes's Theorem is not favorable to Reppert here. Essentially, the existence of other resurrection-type stories that would have been preceding or contemporary with the writing of the gospels indicates that such stories are a likely alternative hypothesis to "someone actually came back to life magically." With evidence of this kind--this many stories, some of which from the Jewish tradition itself and others sharing other similarities with the Jesus narrative--Bayes's Theorem should return a lower posterior probability for the resurrection than whatever prior is assumed. So, erm, go ahead, Reppert, plug it into Bayes's theorem, but don't cheat.

What captured my attention here, leading to this blog post, is how Reppert responded to the above rebuttal.
Why is my definition an odd one? What would you replace it with?
That's all of it. I didn't cut that piece out particularly; it's the whole reply. Out of all of that, all he wants to focus upon is a comment made in passing about his definition? I have already responded and will close this post with my response to Reppert since it makes the major points that I would make from this observation:
First of all, let me note how weak it appears that you've decided only to respond to a nitpicking about a definition instead of to the substance of my argument. In fact, the comment I made about the definition you used was only made in passing, and yet almost inexplicably, it's the only content that you bothered to engage. I say "almost" inexplicably because I have a pretty good guess at the explanation--the usual trick of derail the substance of the conversation to focus on some triviality that may or may not create the appearance of undermining the perception of authority of the person making the argument against you.

Now, I call your definition an odd one because it reads that you would count as evidence anything that is more likely to occur under the conditions. On the one hand, this lets in some specious ideas as "evidence," and this confuses correlation and causation, on the other.

Specious ideas: You already demonstrated this for us. A story of Jesus' resurrection would be more likely if Jesus actually was resurrected. That's relatively undeniable. In strict logic, it reads: "If RESURRECTION, then RESURRECTION STORY." What you're trying to claim is an example of affirming the consequent: "so if RESURRECTION STORY, then RESURRECTION." The implication doesn't go both ways, as my comment clearly illustrated.

If those examples of resurrection-type myths aren't sufficient, perhaps I'll spin a few new ones here and now that consist of "evidence" that a real resurrection happened? You'd reject that as ridiculous because you actually understand that affirming the consequent is logically invalid--except when it comes to something you want to have established. This is why I call faith a cognitive bias.

Correlation and causation: As is well known, performance on certain kinds of intelligence tests come out remarkably higher for people with larger shoe sizes than for people without. This would mean, by your definition, that we might be able to conclude that larger shoes (or feet) imply more success on certain kinds of intelligence tests (with the implication of "more intelligence"). This inference is incorrect, though, because it confuses correlation and causation. Hopefully you'd expect it? Can you explain it? I can: adults, on average, wear bigger shoes than kids, and the tests referred to happen to be IQ tests written for adults, ones that kids have a hard time understanding.
Since the theme I want to convey in this post, aside from some notes about Bayes's theorem, is this diversionary tactic, the only thing I'll add to this response is that the usual trick of derailing the conversation would proceed this way if engaged in: Nitpick about the comment about the definition, get me to offer an alternative definition, and then waste time arguing over which definition is better. This allows the apologist to continue talking, continue avoiding his burden of proof, and appear knowledgeable (about words and perhaps scripture), all without adding the first bit of real substance to the conversation.

I consider this more evidence, by decent standards, that a (perhaps the) primary goal of religious apologetics is to distract from the apologist's burden of proof.

1 comment:

  1. This exchange was quite telling:

    James Lindsey -

    "That's not at all what I mean. I'd accept as some significant degree of credible evidence of the claims of Christianity that Christian prayers actually get answered in a statistically significant way distinguishable from chance."

    Victor Reppert's reply -

    "Some prayer studies seem to suggest this."

    Lindsey -

    "Careful, Victor, you're bordering on cherry picking."

    Reppert -

    "Why? I was linking to a site that offered a number of prayers studies, with differing results. I was rebutting the charge that scientific evidence had unambiguously shown prayer to be of no efficacy. Cherry picking won't be necessary for that."