(Well, ****. My post is too long. I hate when that happens. So I'll try to post part one and part two in rapid succession.)
Smoke, you've mentioned two very different groups in the above paragraph:
1) Scholars who think Jesus never existed...
2) Scholars who think Jesus actually existed...
You omit mention of a third possible group"
3) Scholars who have no opinion one way or the other
And you present no data at all to support the claim that a near consensus exists in group 2. Instead, you just repeat what we get from Christians, who sometimes use this argument of a "near consensus" as if it were proof of something instead of a blatant appeal to popularity ("near consensus") and authority ("serious, reputable"). I agree that a majority of historians who have published on the subject appear to believe that Jesus was a real person, but most of these same historians are Christians (at least in upbringing) who take it as an article of faith that he existed.
I haven't encountered scholars who work in this area and have no opinion one way or another, either in life or in my reading, but I'll admit they're a possible group.
All
consensus means is the majority, dominant opinion. It doesn't mean absolute unanimity. I think it's obvious that the opinions of serious, reputable scholars ought to have more weight than the opinions of self-published cranks and enthusiasts, regardless of whether those scholars are Christians or former Christians. In fact, I would say that the ability to distinguish one's academic discipline from one's faith is the sine qua non of serious, reputable scholarship.
And I didn't say that the scholarly consensus was proof that Jesus existed, though I do think it's something to consider. I was responding to the claim that there was no consensus.
Paul was also the earliest source of information we have on the Jesus cult. I don't consider this brief mention to be very convincing evidence of the historicity of Jesus. It's not as if everyone who proselytized a religion back in those days was telling the literal truth about all of their experiences. The interesting thing about such details of Jesus' life is that they grow more and more elaborate in later documents, suggesting a pattern of embellishment. Paul himself hardly said anything about the life of Jesus. We have no details of a large segment of his childhood, yet you would think that Paul would have had more to say on that subject, having personally met the brother of Jesus. Would he not have had the curiosity to pump James for details?
One of my problems with Paul is that I don't think he was very interested in the historical Jesus. I think he just found Jesus a convenient hook on which to hang his own peculiar religious vision. Nor do I claim that Paul always told the truth, much less the literal truth.
But you're missing the point. Paul had an adversarial relationship with James. He had no motive to acknowledge James as Jesus' brother; the relationship puts Paul at something of a rhetorical disadvantage. Nevertheless, he did acknowledge the relationship, and I think it's reasonable to conclude that he did so because there was no way around it. James was known -- by people who, unlike Paul, actually knew Jesus -- to be Jesus' brother.
James seems to have been, contrary to the supremacy of Peter and Paul in later Christian thought, the unchallenged leader of the Jesus community, a position that likely had a lot to do with his relationship to Jesus. Paul is proud to say that in his disagreement with James he withstood Cephas [Peter] to his face, but it's notable that Peter didn't withstand James to his face, and there's no evidence that Paul ever did so, either.
I would go farther and say that the later claims in the gospels that Jesus' brothers didn't believe in him were probably a conscious Christian attempt to discredit the Ebionism (or proto-Ebionism) of James.
I don't know why this bizarre report makes the Jesus story sound more plausible to you. It sounds like just another story that was tacked on to the main narrative. If anything, the awkwardness of the tradition makes it sound unlikely to be true. From a Christian perspective, why would a man without sin seek out or need a baptism? What was being cleansed from his soul?
Well, exactly. That's precisely my point. Christians had no motive to create such a myth. Unlike the Virgin Birth, for instance, or the Resurrection, it doesn't gibe very well with Christianity. It doesn't fit; it doesn't make sense. I conclude that because Christians had no motive to invent the story, the most likely scenario is that they didn't invent it. On the contrary, they seem to be a little defensive about it, trying -- without success in my opinion -- to explain a story that was already current and made them uncomfortable.
I don't see how this has a bearing on the historicity of Jesus. According to Elaine Pagels, that may have been the prevalent belief before the elevation of Christian orthodoxy to state religion in the Empire. The Virgin Birth and divinity of Christ would have been very important to Constantine, who wanted a religion that would be worthy of Roman power. How could the central figure not have both those qualities when past emperors had them? Caesar Augustus was also supposedly the product of a Virgin Birth, and emperors were generally considered divine.
I haven't read everything Pagels has written, but if she made these claims she was definitely overreaching. Both of these beliefs were widespread in Christianity before Constantine, and the Virgin Birth was uncontroversial in the fourth century. Both the Orthodox and the Arians believed in the Virgin Birth. (And Augustus' mother, by the way, was not believed to have been a virgin even by pagans, and certainly not by Christians.) Constantine was more concerned with uniformity in Christianity than with the details, and described the controversy over the divinity of Christ as a trivial matter. His Arian sympathies have often been noted, and he was baptized by an Arian. The idea that he forced the doctrine of the divinity of Christ onto the Church is not credible.