In my time traveling through the mire of debating Creationists (both occasionally IRL and on the series of tubes) one of the questions I get from them is “What is the best evidence for evolution?”. Before I even considered myself a Bayesian, I started to realize that this was a trick question, especially after Creationists would attempt to refute that “best evidence”.
On my website about the evidence for the theory of evolution, I list a bunch of evidence and then their explanation in an evolutionary framework. In a Bayesian sense, all of this evidence increases the probability of evolution, since their absence would decrease the probability of the theory of evolution. And that’s the point; the best argument for evolution is that there is so much evidence accumulated together for evolution. Which is the Bayesian answer.
Historical Jesus scholars should follow the same reasoning when dealing with mythicism. There is no “best argument” for the historical Jesus. The best argument should be a cumulative Bayesian one, meaning that the best argument for the historical Jesus is (or should be) that there is so much evidence for the historical Jesus. That’s certainly what I would do, and that is certainly what Richard Carrier will do in his forthcoming book about the historical Jesus (though he will be arguing the negative for Jesus’ historicity).
For example, Bart Ehrman, whenever questioned about whether Jesus existed or not, usually falls into the analogous Creationist trap above. He notes the best evidence for why he thinks Jesus existed which is essentially using the criterion of embarrassment. This fails for two reasons: One, like I wrote above, any “best argument” has the possibility of being wrong which if it is, then this gives the opposition the opportunity to claim victory. And two, even if that logic weren’t the case, criteriology can never uncover “evidence”. A criterion of embarrassment is an interpretation of evidence, not the evidence itself. The only way that Ehrman’s argument could be foolproof, and admitted into the evidence bin, is if it were formulated like this:
P1: All people in antiquity didn’t invent dogma that was embarrassing
P2: All Jews in antiquity were embarrassed by a crucified messiah
P3: Jesus was crucified
C: Therefore, Jesus was not invented
This argument is only as strong as its weakest premise. Do we know that all people in antiquity didn’t invent embarrassing details of their religions? Do we know that the Jews were Borg-like entity with one monolithic thing that they were embarrassed by? The same failure happens when scholars appeal to Paul meeting James the brother of the lord as a “slam dunk” argument. There are no slam dunk arguments; the only “slam dunk” should be the accumulation of evidence.
Usually, though, when dealing with Creationists, I lay out all of the evidence and then ask them to explain it using their Creationist framework (e.g. how do you explain both Endogenous Retroviruses and Ring Species using one framework?). More importantly, I ask them what is the least likely type of evidence we would expect to see given Creationism. That is the principle of falsifiability, explained using Bayesian conditional probability terminology. Historical Jesus scholars should do the same, instead of listing hypothetical documents that aren’t in evidence; they can’t be in evidence because they’re hypothetical (if you have to appeal to a hypothetical document to support your hypothesis, this makes your initial hypothesis less likely).
For example, under a mythicist framework, when talking about the original language that a pericope is written in, the least likely evidence would be… absolutely nothing. There’s no restriction on the language that a pericope would originally be written in. This means that there is no language that is the most or least probable given mythicism, making mythicism unfalsifiable when it comes to language evidence. Which is a strike against mythicism. That should be the strategy that historical Jesus scholars engage in when dealing with mythicism. On the other hand, given that Jesus was such a charismatic preacher that that was why his followers revered him and exalted him to the right hand of god after death, what is the least likely evidence we would see? The least likely evidence would be the absolutely zero quotes of his so-called charismatic preaching in any NT writings until around the time of Marcion and Justin Martyr; a full 100 years after Jesus was supposed to have lived**. If you didn’t read any gospels and only the epistles written in the first 100 years of the Christian religion, the last thing you would come away with was how much Jesus’ teachings influenced the new religion.
So as of right now I’m extremely disappointed in the way that historical Jesus scholars have been arguing against mythicism. They need to think more rigorously and scientifically, using actual logical reasoning instead of faulty criteriology and waving around invisible — hypothetical — documents. What I’m seeing is the same sort of reaction that Christian apologists have when trying to defend the truth of their god’s existence or the resurrection; being well read but not knowing anything about formal logic or even probability theory to ensure that they’re not promoting logical fallacies. Maybe the whole enterprise is inherently apologetic in nature, as Hector Avalos argues in The End of Biblical Studies.
** Of course, I’m excluding the four gospels because no one seems to be aware of their Jesus-the-teacher content until Marcion and Justin Martyr