A man with a charismatic and dynamic personality claims to be a prophet and claims to have had an encounter with a heavenly being who reveals previously unknown spiritual truths. The man claims that the heavenly being confirmed the revelation tangibly and physically. Some people are persuaded that the man is telling the truth while others think he is a crackpot. Even for skeptics it is hard to be certain whether he is a deluded lunatic, a pathological liar, or a charlatan.
The prophet claims that the heavenly being had once been a flesh and blood man who walked the earth and stories are invented about the man's activities. However, the initial focus of the earliest believers is on the new spiritual truths that have been revealed and the way in which these truths fulfill the holy writings that are already widely accepted in the culture. Some of the early believers also claim to have had physical and tangible experiences that corroborate the prophet's claims.
As time goes by, substantial numbers of people are converted to the new beliefs without the slightest bit of evidence to confirm the appearance of the heavenly being, the physical corroboration of the revelation, or the historicity of the stories about the heavenly being's activities when he walked the earth. All they have to rely on is the claims of the prophet and his earliest followers.
Many people in the surrounding community think that the prophet is a charlatan and that his claims are utter hogwash. These people try to persuade the believers of the foolishness of the prophet's claims. Some are convinced and fall away, but those who remain become even more fervent in their beliefs. The prophet tells them that the skeptics are servants of the devil who should be ignored. He tells them that the fate of their everlasting souls depends upon unwavering commitment to the teachings of the new faith.
The believers endure many hardships on behalf of their new faith. They put their reputations, wealth, and at times even their lives at risk. They endure abuse and persecution from outsiders. This causes some to fall away, but those who remain are drawn closer together. They begin to see themselves as a separate people and they shun contact with the rest of society. Anyone who fails to maintain sufficient commitment to the teachings of the prophet is cast out as a heretic.
The new religion continues to spread and within the course of a couple hundred years, it has millions of adherents. Nevertheless, there is never a shred of credible evidence to support any of their supernatural beliefs.
I think that most scholars who believe that Jesus was a historical person would accept that this is a more or less reasonable characterization of the founding and spread of the Church of Jesus Christ of Latter Day Saints. (The exception would be those historical Jesus scholars who are also Mormons.) Nevertheless, most historicist scholars think it preposterous to suppose that any sort of similar dynamic could have been at work in the origin and early spread of Christianity rendering Jesus of Nazareth as complete a fabrication as Moroni, the Warrior-Prophet of the Nephites. They believe it reasonable to express a high degree of confidence that there was a historical person behind the visions that Paul and others claimed to have.
I will confess that I have purposely used ambiguous language in describing Joseph Smith and the origins of Mormonism in order to highlight the parallels with Paul and the origins of Christianity while obscuring the differences. I will also acknowledge that some of the differences may be of sufficient weight to justify belief in a historical Jesus while rejecting belief in a historical Moroni. Nevertheless, most of the reasons I usually see given for why Christianity couldn't have grown and spread in the way that it did without a historical Jesus seem to be predicated on the idea that 1st century Christians were markedly less gullible and superstitious than 19th century Mormons.
For example, a historicist might rightly point out that early Christians believed in a heavenly being who had walked the earth as a man within living memory while the first Mormons believed in a heavenly being who had walked the earth as a man fourteen hundred years earlier. The important point to me, however, is that the early Mormons believed in both the heavenly being and the man with absolutely no evidence whatsoever other than the word of Joseph Smith. Is there any way to establish that the earliest Christians had any better evidence than the word of Paul who had claimed to have seen the heavenly being but seemed to know almost nothing about the man who walked the earth?
Historicists can also point out that it would have been possible to investigate claims about an actual human being named Jesus who had walked the earth within living memory and that there would be people around who could debunk false claims. On the other hand, it was been possible to investigate many of Joseph Smith's claims as well and there were plenty of people who tried to expose him as a fraud. However, Smith managed to convince most of his followers that their eternal destinies rested on their willingness to ignore skeptics and unbelievers. As a result, the people who accepted Smith's claims without question were not deterred by the people who investigated them and found them wanting. Is there any reason to think that the earliest Christians wouldn't have been just as willing to ignore evidence that contradicted their beliefs?
Another difference that might be noted is that the experiences that corroborated Joseph Smith's encounter with the Angel Moroni and the Golden Plates took place after Smith's among his followers while the experiences that corroborate Paul's experience are thought to have taken place before Paul's among his predecessors. This might be significant, but the first account of the events that corroborate Paul's experience come from Paul himself some twenty years after they are thought to have occurred, while the accounts that corroborate Smith's experience are much closer in time to the events themselves, and are purportedly verified by the people who experienced them. I am not sure that this difference makes Paul's account the more credible one.
One of the differences that many scholars scholars cite as significant is the incongruity of a crucified Messiah to first century Judaism. Dr. James McGrath describes the argument this way:
The reason that the crucifixion persuades most historians that Jesus was a historical figure is that a crucified messiah was in essence a contradiction in terms. . . . It needs to be emphasized that we are talking about a dying and rising messiah. And the messianic expectations of Judaism around the time of early Christianity are well documented. And the whole notion of messiah is “anointed one” . . . . and this goes back to the practice of anointing kings and priests in ancient Israel. And in the case of Jesus the connection of the terminology of the term messiah with the claim to his having been descended from David shows they were thinking of a kingly figure. And nothing would have disqualified someone from seriously being considered possibly being the messiah as being executed by the foreign rulers over the Jewish people. That wasn’t what people expected from the messiah. And it makes very little sense to claim that the early Christians invented a figure completely from scratch and called him the messiah and said that he didn’t do the same things that the messiah was expected. Not only did he not conquer the Romans, he was executed by them. He did not institute and bring in the kingdom of god the way the people were expecting, and in fact Christians had to explain this in terms of Jesus returning to finish the task of what was expected of the messiah.According to Dr. McGrath, belief in the resurrection was most likely a result of the cognitive dissonance that Jesus' followers experienced after he was put to death by Romans who he had been expected to conquer.
All of this makes much more sense if one says that there was a figure whom the early Christians believed was the messiah and that the early Christians were trying somehow to make sense of those things that don’t seem to fit that belief.
My problem with this argument is that I an unaware of any objective criteria by which one would assess the probability that any particular supernatural story might be invented by a particular individual in a particular culture and the probability that the story might be believed by large numbers of his peers. Are historians really able to accurately identify the factors that distinguish a supernatural story that might be invented and believed in 19th century upstate New York from one that couldn't have been invented and believed in 1st century Palestine? When evaluating the probability that people of a particular culture might accept a particular story, can any evidence possibly be more significant than the fact that many of them did accept the story? Moreover, if it can be shown that large number of people did accept a story, how does one go about assigning a low probability to the possibility that someone might invent it?
All in all, I still see no reason to conclude that it is more likely than not that Jesus of Nazareth was a complete fabrication. The idea that the resurrection stories were the product of the cognitive dissonance experienced by the followers of a failed apocalyptic prophet seems perfectly plausible to me. Nevertheless, I have yet to see an argument that convinces me that there is any principled basis to assign a significantly higher probability to that than the possibility of invention by a uniquely imaginative personality. Hence, I remain agnostic about a historical Jesus.