I think there was a historical Jesus and we can learn some things about him. Mind you, this is of course not the same as saying that the theological Jesus existed. There is a big difference. What I am going to do now is present common mythicist claims and debunk them or prove them irrelevant.
Claim 1: The Gospels can’t be used as historical sources.
Mythicists often say that the bible can’t be used as evidence. It all depends on what you are trying to prove. Just because something is in the bible, doesn’t mean it can be of no historical value to us. What people often tend to forget is that none of the authors in the bible knew that their book would someday be in something called the bible. Dismissing the Gospels from the get go is on purely ideological reasons, not historical, as New Testament scholar Bart Ehrman says in his book “Did Jesus Exist?”:
“We don’t dismiss early American accounts of the Revolutionary War simply because they were written by Americans. We take their biases into consideration and sometimes take their descriptions of events with a pound of salt. But we do not refuse to use them as historical sources. To refuse to use them as sources is to sacrifice the most important avenues to the past we have, and on purely ideological, not historical grounds. So too the Gospels. Whatever one thinks of them as inspired scripture, they can be seen and used as significant historical sources.” (page 74)
Claim 2: No author outside of the New Testament mentions Jesus.
This is simply not true. Roman historian Tacitus mentions Jesus in his Annals of the Imperial Rome and so does Josephus in his famous Testimonium Flavianum. Mythicists will often say that the quote by Josephus is an later Christian interpolation, but this is not true entirely. There is an interpolation indeed, but when the interpolation is removed, the text probably goes something like this:
“At this time there appeared Jesus, a wise man. He was a doer of startling deeds, a teacher of people who receive the truth with pleasure. And he gained a following both among many Jews and among many of Greek origin. When Pilate, because of an accusation made by the leading men among us, condemned him to the cross, those who had loved him previously did not cease tot do so. And up until this very day the tribe of Christians, named after him, has not died out.”
But even if we didn’t have any writings about Jesus within a hundred years after his death, does this automatically mean he never was born? Of course not. What mythicist often do is compare Jesus to Julius Caesar. There is historical evidence for the latter, they claim, and none for Jesus. But is this a valid comparison? Is comparing a Roman emperor with a lower-class Palestinian Jew the way to establish who was born and who wasn’t? Of course not. Did Pontius Pilate not exist? Most of what we know from him we get from the Gospels. And he was a very important man in Judea at the time. We have very little to go on to prove he existed and it’s a myth that the Romans kept close records of everything. If they did, then where are those records? What this means is that we have to look for other evidence to prove the probability of someone’s existence in the Ancient world.
Claim 3: Nazareth did not exist
Unfortunately for the mythicists, there is archaeological evidence that Nazareth did exist at the time of Jesus , but I don’t need to go over that evidence to prove my point. Proof that Nazareth did or did not exist is exactly that: proof for the existence of Nazareth. It tells us nothing about the existence of Jesus. Think of it this way: whether or not Obama was born in Kenia or the U.S. is irrelevant to the question of whether he was born at all.
Claim 4: The Christ figure is based upon other dying and rising gods/pagan gods
Osiris, Attis, Adonis, Tammuz, Heracles, Melqart, Eshmun, Baal, and so on and so forth. Mythicists claim that the Jesus figure was based upon other pagan gods. But before I do debunking the above, ask yourselves, so what if the figure was based upon the dying and rising gods? If people over 50 years start telling the craziest stories about me, that I for instance, made love to 50 women at once and impregnated them all at the same time, does this mean I did not exist or is it just a nonsense story attributed to a real historical figure? Does this mean there is a historical figure upon which the stories of Hercules are based? Maybe. We don’t know. But the problem in that case is that we do not have the sources to prove there ever was a historical Hercules and we do have those for Jesus.
Bart Ehrman writes in his book “Did Jesus Exist?”:
“There are two major problems with the view that Jesus was originally invented as a dying-rising god modeled on the dying and rising gods of the pagan world. First, there are serious doubts about whether there were in fact dying and rising gods in the pagan world and if there were, whether they were anything like the dying and rising Jesus. Second, there is the even more serious problem that Jesus could not have been invented as a dying and rising god because his earliest followers did not think he was God.” (page 222)
So the whole argument is already on shaky ground but let’s have a look at one of those pagan gods who mythicists claim was a template for Jesus, Osiris. Osiris was an Egyptian god about whom a good deal was written in the ancient world. We have texts discussing Osiris that span a thousand years. None was as influential or as well known as the account of the famous philosopher and religion scholar of the second century, Plutarch, in his work Isis and Osiris. According to the myths, Osiris was murdered and his body was dismembered and scattered. But his wife, Isis, went on a search to recover and reassemble them, leading to Osiris’ rejuvenation. The key point to stress, however, is that Osiris does not return to life. Instead he becomes the powerful ruler of the dead in the underworld. And so, for what we can learn from historical writing, Osiris does not rise from the dead
Let me also debunk the Mithras comparison for you. Its comparison is probably based on a essay published by Frank Zindler called: “How Jesus got a life”. Frank Zindler goes out go his way trying to prove that the Jesus figure was inspired by Mithraism, but provides us with no evidence whatsoever. It’s all made up. Scholars of Mithraic mysteries readily admit that as with most religions, we do not know a good deal about Mithraism, or nearly as much as we woud like to know , yet Zindler makes all these wild claims based upon nothing. The Mithraists left no books behind to explain what they did in their religion and what they believed. Almost all of our evidence is archaeological. There is no Mithraic text telling us Mithras was born of a virgin on the 25th of December and that he died to atone for our sins only to be raised on Sunday.
The mythicists position isn’t a terribly good position and it’s arguments can be debunked fails easily doing the proper research or are either highly irrelevant to the question whether Jesus existed or not.
 Surveys and Excavations at the Nazareth Village Farms: Final Report. page 16-79. Stephen J. Pfann, Ross Voss and Yehudah Rapuano
 The Religion of the Mithras Cult in the Roman Empire: Mysteries of the Unconquered Sun – Roger Beck
 Bart Ehrman – Did Jesus Exist?