Written by John W. Loftus.
Here I'm going to offer some brief comments on Craig's main argument against Ehrman, found in Craig's first rebuttal
linked here.
Against Ehrman he uses the mathematical formula of Bayes's theorem. But what's left out of any equation of this type (as well as Swinburne’s conclusion where he thinks it’s 97% probable Jesus arose from the dead) is that the opponent can object to the values set by the one using the argument.
Here’s Craig (in blue throughout):
And now we’re ready to see precisely where Dr. Ehrman’s error lies. So in the grand tradition of Hume’s Abject Failure, I give you: Ehrman’s Egregious Error.
This is cute and is merely a rhetoric device to label what it is your opponent purportedly does. The mere labeling of this supposed error has no substance to it.
Craig:
He says, “Because historians can only establish what probably happened, and a miracle of this nature is highly improbable, the historian cannot say it probably occurred.”
This appears to be a historian’s version of what is known in scientific circles as methodological naturalism, which assumes that for everything we experience there is a natural cause. We who live in the modern world operate on this assumption ourselves everyday. This assumption is the foundation of modernity. It is what defines us as modern people. In previous centuries we either praised God for the good things that happened to us, or we wondered why he was angry when bad things happened in our lives. But by scientifically investigating into the forces of nature we can better run our own lives, and we know how to make life easier for ourselves, with fewer diseases.
In scientific fields methodological naturalism is a way to gain the truth about nature, and it has astounding results. Some scientists go so far as to claim that since it works, then nature must be ultimate, but that doesn’t follow, for the later conclusion is beyond the scope of science; it is a metaphysical claim. [For discussions about this see “Methodological Naturalism?” by Alvin Plantinga, which can be found at: www.arn.org, “Justifying Methodological Naturalism” by Michael Martin, and “Methodological Naturalism and the Supernatural,” by Mark I Vuletic, to be found at www.infidels.org/library].
Still, if such an assumption has had so many successes in science, then why not apply that method to history as well? And modern historians have done just that. When looking into the past they assume a natural explanation for every historical event. They are taught to be critical of the past, as we’ve just mentioned. As historians they must. That is the standard for what they do as historians, to be skeptical of the past record, especially claims of the miraculous.
According to I. Howard Marshall in I Believe in the Historical Jesus (Eerdmans, 1977) “many historians—the great majority in fact—would say that miracles fall outside their orbit as historians. For to accept the miraculous as a possibility in history is to admit an irrational element which cannot be included under the ordinary laws of history. The result is that the historian believes himself justified in writing a ‘history’ of Jesus in which the miraculous and supernatural do not appear in historical statements. The ‘historical’ Jesus is an ordinary man. To some historians he is that and no more. To others, however, the possibility is open that he was more than an ordinary man—but this possibility lies beyond the reach of historical study as such.” (p. 59).
Craig:
In other words, in calculating the probability of Jesus’ resurrection, the only factor he considers is the intrinsic probability of the resurrection alone [Pr(R/B)]. He just ignores all of the other factors. And that’s just mathematically fallacious. The probability of the resurrection could still be very high even though the Pr(R/B) alone is terribly low. Specifically, Dr. Ehrman just ignores the crucial factors of the probability of the naturalistic alternatives to the resurrection.
Notice the words highlighted? This too is rhetoric. Ehrman does not judge his case against the resurrection in a vacuum. No one does. There are other factors that play into anyone’s assessment of the resurrection. And there is no mathematical fallacy here either. Ehrman just assigns different values to background factors than Craig.
But what value should we place on the intrinsic probability of the resurrection, that is, background factors? That’s the question. Sometimes our background factors against believing in miracles control what we believe so strongly that it would require evidence so complete and overwhelming that one is hard pressed to see that any event, especially in the past, can overcome them. It's not terribly unlike how much evidence it would take to overcome your belief that the Holocaust occurred despite the naysayers, except that with the resurrection we're dealing with a purportedly supernaturally caused event. Likewise, how much evidence would it take to overcome your belief that aliens have not abducted people? What background factors are important here are even hard to specify.
Listen to Gotthold Lessing here: “Miracles, which I see with my own eyes, and which I have opportunity to verify for myself, are one thing; miracles, of which I know only from history that others say they have seen them and verified them, are another.” “But…I live in the 18th century, in which miracles no longer happen. The problem is that reports of miracles are not miracles….[they] have to work through a medium which takes away all their force.” “Or is it invariably the case, that what I read in reputable historians is just as certain for me as what I myself experience?”
Lessing, just like G.W. Leibniz before him, distinguished between the contingent truths of history and the necessary truths of reason and wrote: Since “no historical truth can be demonstrated, then nothing can be demonstrated by means of historical truths.” That is, “the accidental truths of history can never become the proof of necessary truths of reason.”
He continued: “We all believe that an Alexander lived who in a short time conquered almost all Asia. But who, on the basis of this belief, would risk anything of great permanent worth, the loss of which would be irreparable? Who, in consequence of this belief, would forswear forever all knowledge that conflicted with this belief? Certainly not I. But it might still be possible that the story was founded on a mere poem of Choerilus just as the ten year siege of Troy depends on no better authority than Homer’s poetry.”
Someone might object that miracles like the resurrection of Jesus from the dead, are “more than historically certain,” because these things are told to us by “inspired historians who cannot make a mistake.” But Lessing counters that whether or not we have inspired historians is itself a historical claim, and only as certain as history allows. This, then, “is the ugly broad ditch which I cannot get across, however often and however earnestly I have tried to make the leap.” “Since the truth of these miracles has completely ceased to be demonstrable by miracles still happening now, since they are no more than reports of miracles, I deny that they should bind me in the least to a faith in the other teachings of Christ.” (“On the Proof of the Spirit and of Power,” [Lessing’s Theological Writings, (Stanford University Press, 1956, pp. 51-55)].
Back to Craig;
In order to explain that the resurrection is improbable, he needs not only to tear down all the evidence for the resurrection, but he needs to erect a positive case of his own in favor of some naturalistic alternatives.
Okay, so we first have the intrinsic probability of the resurrection, and then we have the evidence. The intrinsic probability for Ehrman is extremely low. When it comes to the evidence, Craig suggests he needs to criticize arguments for the resurrection and at the same time present an alternative theory to explain the present evidence. But if the intrinsic probability of a miracle is close to zero, then I see no reason why Ehrman should have to present an alternative theory of what happened at all. Any theory he might present, even if implausible as he said, would have a greater degree of probability than a resurrection from the dead, given Ehrman's background knowledge,
Craig:
But that’s not all. Dr. Ehrman just assumes that the probability of the resurrection on our background knowledge [Pr(R/B)] is very low. But here, I think, he’s confused. What, after all, is the resurrection hypothesis? It’s the hypothesis that Jesus rose supernaturally from the dead. It is not the hypothesis that Jesus rose naturally from the dead. That Jesus rose naturally from the dead is fantastically improbable. But I see no reason whatsoever to think that it is improbable that God raised Jesus from the dead.
In order to show that that hypothesis is improbable, you’d have to show that God’s existence is improbable. But Dr. Ehrman says that the historian cannot say anything about God. Therefore, he cannot say that God’s existence is improbable. But if he can’t say that, neither can he say that the resurrection of Jesus is improbable. So Dr. Ehrman’s position is literally self-refuting.
In Ehrman’s defence, he says that a historian cannot say that the resurrection is probable, not that a theologian must do so. But if a theologian concludes Jesus arose, it isn’t based upon the historical evidence. Therefore, Craig’s background knowledge controls what he believes too, and the reason Craig concludes the resurrection occurred is not because of the historical evidence, but because he’s a believing theologian who adopted his faith when he was only 16 years old. [On this click on "John's Posts" in the sidebar and read what I wrote about The Outsider Test].
Besides, Ehrman doesn't have to show that the existence of just any God is improbable. All Ehrman has to do is to show that the existence of the Christian God is improbable. And this would be a case that is easier to make, because in order to make it against Craig all Ehrman would have to do is what we do here at DC on a daily basis with what the Bible says about this God in the Bible. And if the Bible debunks itself, and the Bible tells us about the resurrection of Jesus, then we have an additional reason not to trust what the Bible says about the resurrection.
Craig;
But it gets even worse. There’s another version of Dr. Ehrman’s objection which is even more obviously fallacious than Ehrman’s Egregious Error. I call it “Bart’s Blunder.”
Rhetoric. He’s good at it.
Craig:
Here it is: “Since historians can establish only what probably happened in the past, they cannot show that miracles happened, since this would involve a contradiction—that the most improbable event is the most probable.”
In truth, there’s no contradiction here at all because we’re talking about two different probabilities: the probability of the resurrection on the background knowledge and the evidence [Pr(R/B&E)] versus the probability of the resurrection on the background knowledge alone [Pr(R/B)]. It’s not at all surprising that the first may be very high and the second might be very low. There’s no contradiction at all. In sum, Dr. Ehrman’s fundamental argument against the resurrection hypothesis is demonstrably fallacious.
Ehrman is speaking as a historian from the perspective of methodological naturalism. Ehrman is merely saying that as a historian he cannot step outside what is improbable from the historian’s perspective. In one sense, both Craig and Ehrman agree. They both admit that the intrinsic probability of the resurrection is very low. Because of his studies of the Biblical documents and ancient texts Ehrman considers this intrinsic probability to be extremely low to the point of zero. Ehrman claims that historical evidence cannot lead a historian to believe, and yet even Craig admits that it’s not just evidence, but also background factors which help someone decide that it’s probably true that Jesus arose from the grave. However, these additional background factors, such as the belief in God, are outside the historical evidence too, and hence both of them admit that historical evidence will not in and of itself lead someone to conclude that Jesus arose from the dead.
His book is quite popular, ranking in the top ten "apologetics" category of books on Amazon for several years now. However, Bryan Frances, an Associate Professor of Philosophy at Fordham University, outs him as either clueless, self-deceived or a fraud, in the Introduction of his book, 
See for yourself: