Since the Enlightenment, the Gospel stories about the life of Jesus have been in doubt. Intellectuals then as now asked: "What makes the stories of the New Testament any more historically probable than Aesop's fables or Grimm's fairy tales?" The critics can be answered satisfactorily, but the arguments they put forth are abrasive to naive faith.
Although the birth stories in the Bible may be happy tales of religious hope, many New Testament scholars simply dismiss them as legendary, contradictory, and unhistorical. Here's why. The New Testament contains no clue as to the time of Jesus' birth, though the theme of shepherds watching their flocks in the field by night suggests any time but winter. Christmas, the celebration of Jesus' birth, was placed in December in the fourth century to correspond to the Saturnalia, a popular pagan Roman holiday. We have no record of the census (mentioned only in the Gospel of Luke) in the Roman Empire under Emperor Augustus. Likewise, we have no record that Herod savagely decreed the murder of the male children of Bethlehem (mentioned only in Matthew among the gospels). The birth stories in Luke and Matthew contradict each other not only in the details, but in fundamental ways. Even the famous star over Bethlehem, which would cinch the date of Jesus' birth, is famously ambiguous: Either it was a miracle of a traveling star—which no one else at the time noticed—or it was an astronomic commonplace, leaving us with too many comets, super novae, and planetary conjunctions to locate the year of Jesus' birth with certainty.
In fact, we have absolutely no record of Jesus' existence in any contemporary historical source. All reports of Jesus' life come from believers. The Christian counting of years—the division of the eras of "B.C." (Before Christ) and "A.D." (Anno Domini, or in the year of the Lord)—was imposed upon the calendar centuries afterward and doesn't square with the Gospels. Indeed, if Jesus were actually born in the year 1, Herod the Great would already have been dead for four years. So, either the count is off or the story of Herod's interventions is false. Likely both are wrong.
But do we throw out the life of Jesus along with the historical bath water? I do not think so.
New Testament scholars who wanted to show that Jesus was a historical figure have developed over the last century criteria for judging the historical reliability of a source, like the New Testament, which was entirely written by believers. One criterion is that the story has to have a context in Judaism, as Jesus was born and died a Jew. Another criterion is that multiple sources in the early New Testament must attest to the story. But the most important arrow in the scholarly quiver has been and remains "the criterion of dissimilarity." The criterion sets a high standard: For scholars to arrive at an undoubted fact about the life of Jesus, they must eliminate as possibly biased everything that is in the interest of the early church to tell us. Conversely, for a fact about Jesus to be deemed historical, it must not be in the interest of the church to report it. It must be, in effect, an embarrassment for the early church. Thus, the criterion of dissimilarity is sometimes called the criterion of embarrassment.
Now, this is deliberately a very hard test. Many things that Jesus is reported to have said or done will be eliminated by this criterion. A number of authentic actions and sayings of Jesus will be among them, because we cannot demonstrate them to be free of the bias of the early church. Virtually everything from the Christmas story disappears, except perhaps that Joseph and Mary were not yet officially married. In rabbinic law, a properly contracted engagement might be considered a marriage, so Jesus was not illegitimate according to Jewish law. But we cannot be sure that rabbinic law was in effect in Nazareth before Jesus was born. And Greeks, who had different marriage laws, would have treated the story differently.
I have often heard fellow scholars exclaim in frustration that the criterion of dissimilarity yields such meager results that no one could ever write Jesus' biography based upon it. But that isn't the criterion's purpose. It was designed to help sift through the Gospels for indisputable facts so that scholars could be sure that the stories are, at least in part, historical. It seems to me, as a Jew and so as an outsider, that the criterion also has developed a secondary important function: It cautions Christians of different denominations about getting overconfident about their particular beliefs. Almost all Christians see their own beliefs as grounded in the authentic New Testament facts; the criterion suggests that very few facts are actually undisputable.
For all the rigor of the standard it sets, the criterion demonstrates that Jesus existed. Here are some facts in the Gospels that embarrassed the early church: Jesus was baptized by John (a great theological problem). He preached the end of the world (which did not come). He opposed the Temple in some way (and this opposition led directly to his death). He was crucified (a disreputable way to die). The inscription on the cross was "Jesus of Nazareth, King of the Jews" (the church never preached this title for Jesus and shortly lost interest in converting Jews). No one actually saw him arise (though evidently his disciples almost immediately felt that he had). Ironically, it's the embarrassing nature of these facts that assures us of their authenticity. The exalted figure of Jesus as a heavenly redeemer and the Lord of the Hebrew Bible, on the other hand, was the response of Jesus' closest disciples to the events of Easter morning. These are tenets of faith, not claims that can be demonstrated historically.
The criterion of dissimilarity puts us in a better position with regard to the life of Jesus than we are in with regard to the great events of Israelite history. We have no evidence of Abraham's life or Moses' or of the Exodus either. We have good evidence that the Hanukkah miracle of the cruze of oil that burned for eight days never happened and that the story in the Book of Maccabees is told in an extremely tendentious way.
Lest I start another battle in the fictional war against Christmas, I would no more recommend that we stop celebrating Christmas than I would recommend that we stop celebrating Purim or Hanukkah or Passover. But I would say that historical reasoning should function to keep all of us from being arrogant about the historical claims we make about our religions. Doubt can be a good thing, even in matters of faith, if it keeps us from being intolerant of others' religious beliefs. The Christmas story tells us a great deal about the Judaism of the first century, just as the Judaism of the first century illumines our understanding of Jesus' life. Put another way, the study of earliest Christianity is invaluable for Jewish history while knowledge of Jewish history is crucial for understanding early Christianity.
I wonder, Larry and John, what you would add to the debate or take away, given your ideas about the rise of Christian literature?