Some claim that Jesus—whose birthday Christians and plenty of non-Christians are preparing to celebrate—never existed.
The people of Jesus’ time displayed no such skepticism, but for those of us who demand empirical evidence, Jesus is mentioned in several important sources (other than the New Testament). According to the New Testament scholars Dennis Duling and Norman Perrin, these references describe Jesus as a “wandering artisan” who traveled primarily in southern Palestine and lived in the early decades of what we now call the Common Era.
The principal, extra-Biblical sources about Jesus are Roman, Jewish and Christian. Works written by the Roman historians Tacitus and Suetonius during the early 2nd Century are of interest because they confirm that Christian missionaries arrived in Rome during the timeframe in which Paul wrote his letter to the Romans.
More helpful on the question of Jesus’ existence are the Jewish sources. For example, the historian Josephus (37-100? CE) mentions the execution of James whom he calls “the brother of Jesus, who was called Christ.” Because Christians preserved Josephus’ works through the centuries by hand-copying them, his references to Jesus are suspect—during the copying process, phrases were probably altered or even added to support Christian claims. However, most scholars agree that Josephus’ brief remark concerning James came from Josephus himself.
Another, longer passage from Josephus is more questionable. Phrases unlikely to have been written by a Jewish author were woven into the original. The majority of scholars, however, are of the opinion that this passage was not entirely fabricated.
Here it is, edited to remove the phrases Christian copyists may have added:
About this time there lived Jesus, a wise man. For he was one who wrought surprising feats and was a teacher of such people as accept the truth gladly. He won over many Jews and many of the Greeks. When Pilate, upon hearing him accused by men of the highest standing among us, had condemned him to be crucified, those who had in the first place come to love him did not give up their affection for him. And the time of the Christians, so called after him, has still to this day not disappeared.
Josephus, then, confirms the existence of Jesus who, as Duling and Perrin summarized, “gathered followers, taught, worked miracles, and was crucified under Pontius Pilate.”
This should put to rest the most skeptical of skeptics’ questions about whether Jesus of Nazareth actually lived. A birthday bash celebrating his coming into the world is, quite simply, based on fact.
Granted, questions about the actual day and year remain. No one knows exactly on what day Jesus was born. On this point, the sources are silent.
But, really, does it matter whether we’ve got the right date?
Even if you’re a Christmas-celebrating non-Christian, given the short, dark days of winter, isn’t a festive time of twinkling-lights and sweets-galore and family-time perfect right now?
All things considered, if we’re going to celebrate Jesus’ birthday, December 25 seems as good a day as any.
Reference: Dennis Duling and Norman Perrin, The New Testament: Proclamation and Parenesis, Myth and History, 3rd ed. (Fort Worth, TX: Harcourt College Publishers, 1994).
The Naked Theologian 
The real answer to the question is, of course, ‘I don’t know’. I often wonder why so few people are comfortable with ‘I don’t know’ as an answer.
The further we go back in time the less certainty we have about what really occurred in history. We have only had video, audio, photographs, and other recorded media for a relatively short period of human history.
Thanks God that we do have video documentation for things like the atrocities committed during WW-II.
However, once you go back in time the evidence becomes more and more limited and questionable. It soon literally amounts to little more than hearsay.
We know that human beings can be irrational creatures, easily fooled. After all we have only experienced scientific enlightenment in just the past century.
It has been mere decades that we have just now begun to understand evolution, DNA, biology, cosmology and particle physics. Yet, still, mysteries abound in the Universe.
The further you go back in time the more people describe natural phenomenon in supernatural terms. The more people repeat stories and myths then the evolution of those stories accumulates over time.
As we go back further we deal with dead languages and cultures where a tremendous amount of true meaning is lost, by definition, because the original culture itself is long gone.
What can we truly know as true, or not true, as we go back further and further in time?
Add to this an almost absurd amount of cultural relativism where one tiny tribe who just happened to have their stories preserved are held in reverence while religious writings literally thousands of years older are ignored by Western culture.
Has anyone else played the telephone game?
What we truly can know as ‘truth’ about the past is extremely limited. Did a character who is analogous to the Christ figure literally exist in space and time some two thousand years ago?
Maybe. Who can say for sure. Did he perform miracles? Well, as far as we can tell today miracles are impossible and violate the known laws of physics and reality so, quite likely not.
Can stories be embellished ten minutes after they are originally told? How about ten days? Or ten months? Or ten years? Or ten decades; which is closer in duration of time that the gospels were allegedly written in their original form?
It worries me that modern man places more stock in the ancient writings, told, retold, written and rewritten, scribed and transcribed, over the course of thousands of years, than what we can actually see, hear, and touch using all of the advantages of the scientific method, logic, reason, and rational thought today.
Jesus? I don’t know. The Universe. I do know.
John