In the classic South Park episode All About Mormons, Joseph Smith tells various people about the supernatural comings and goings in his life. Not everyone believes him, but those who do say "Sure. Why would he make that up?" I think that the most disappointing thing in Did Jesus Exist is that Bart Ehrman resorts to a similar argument:
Before the Christian movement, there were no Jews who thought that the messiah was going to suffer. Quite the contrary. The crucified Jesus was not invented therefore to provide some kind of mythical fulfillment of Jewish expectation. The single greatest obstacle Christians had when trying to convert Jews was precisely their claim that Jesus had been executed. They would not have made that part up. (Did Jesus Exist? p. 173)To illustrate the problems with this argument, let's recast it:
Before the Mormon movement, there were no Protestants who thought that there might be undiscovered books of scripture that were every bit as inspired, inerrant, and authoritative as the books of the Bible. Quite the contrary. The single greatest obstacle Mormons had when trying to convert Protestants was precisely their claim that Joseph Smith had found another New Testament of Jesus Christ buried in western New York state written on Golden Plates. They would not have made that part up.
If we must believe that there was a historical reality behind the concept of a crucified messiah because we think the idea would have been absurd and offensive to most Jews of the time, why shouldn't we believe that there was a historical reality behind the Golden Plates?
According to Ehrman this is one of the especially key points that "shows beyond a shadow of reasonable doubt that Jesus must have existed as a Palestinian Jew who was crucified." (P. 144) I'm sorry Dr. Ehrman. I love your stuff, but this can't be a good argument.
In support of this claim, Ehrman makes the very same kind of argument from silence for which he berates the mythicists. "We do not have a shred of evidence to suggest that any Jews prior to the birth of Christianity anticipated that there would be a future messiah who would be killed for sins--or killed at all--let alone one who would be unceremoniously destroyed by the enemies of the Jews." (p. 170) Should we expect to have evidence of what every single Jew prior to the birth of Christianity anticipated? How could we possibly know such a thing.
Let me suggest what seems to me to be a perfectly plausible scenario.
There is a devout Jew named Saul living in the first century who really really wants a messiah to come and overthrow the Romans. Every time he hears about someone claiming to be the messiah, he gets his hopes only to have them dashed when the Romans crush the troublemaker. He struggles to understand why this keeps happening again and again. Then one day, a thought pops into his head, "Maybe this is part of God's plan." He searches through the scriptures and he finds all those same verses that Christians always cite as prophecies of Jesus' passion. One night he has a dream in which he sees an exalted heavenly being who tells him "I had to suffer for Israel's wrongdoing but now God has raised me up and I'll be coming back to kick some Roman ass."Voila! There's your crucified messiah without there having to be any specific historical person behind it.
Do I think that's what happened? I don't know, but I don't see how we can possibly know beyond a shadow of a reasonable doubt that it couldn't have happened. The scenario that Ehrman and others lay out basically amounts to Jesus' followers stumbling onto the idea of a crucified messiah as a result of grief induced hallucinations that they experienced after his crucifixion. I find that perfectly plausible. What I find implausible is the idea that historians can be so sure of what every first century Jew thought as to be certain that no one could have possibly stumbled on the idea in any other way.