Some atheists attempt to undermine Christianity by arguing that Jesus never existed - He's a myth like many other god-myths in history. The dying-and-resurrected-messiah myth is one such attempt that Greg dismantled in Solid Ground earlier this fall. These critics claim Josephus, a Jewish historian who records that Jesus lived and His followers believed He was the Christ, is completely compromised. That's not true - even taking the most severe questions into account, Josephus's record remains intact. It's simply not the case that there is serious question among scholars that Jesus didn't exist.
Recently on the radio show, Mike Licona mentioned an interesting bit of information. Even the Jesus Seminar, a group with radical skeptical views of the Bible, don't consider the question of Jesus' existence a serious question of debate. They're anxious to debate many of the New Testament details of Jesus, but not the fact of His existence.
They turned down an offer to publish an artcile by Early Doherty on Jesus as myth. Doherty reported:
A recent proposal [was] made to the editor of the Fourth R, the magazine of the Westar Institute, the umbrella organization for the Jesus Seminar. This person, who is familiar with and has admired my work (no telling the crazy things some people will support, right?) noted to the editor that the Fourth R has a tradition of presenting some pretty liberal viewpoints for examination. He offered to donate $5000 to the magazine if they would print a substantial article by myself on the Jesus Myth question, accompanied in the same issue by an equal counter-article by any scholar of their choosing, to be followed in a subsequent issue by shorter rebuttals by both myself and the other scholar. (This offer, by the way, was made without my prompting or even my knowledge, until he informed me after it was made.)
This was the response he received:
I'm not presently inclined to devote an issue to questioning the existence of Jesus. The topic is a perennial one among skeptics. If someone wants to doubt the existence of Jesus, my experience is that no evidence or argument will change his mind. Such is the nature of skepticism. But the existence of Jesus is not a living issue among historical Jesus scholars. Perhaps it should be, but it just isn't, at least at present. With so many other living issues to explore, I don't think it would be responsible to devote the limited space in the 4R to your suggestion.
So even one of the most liberal groups dismisses these myth claims as unserious.
And here is Mike Licona's review of the film "The God Who Wasn't There" that is mentioned in the link above. Mike critiques the case that Jesus is merely a myth.
