The Jesus myth claims that Jesus never existed and that his story is not based on history but on myth. Jesus would be no different than Horus or Dionysus.
If the Jesus myth is true, we need to deal with the nature of the Gospels, which are our primary sources for the life of Jesus. We need to ask: Did the writers of the four canonical Gospels believe that Jesus was a historical figure or did they know that Jesus was not real and were working toward creating a new myth?
I would like to just focus on Luke (not that I think the others had a different aim). I’m going to share a couple of passages and ask how we should interpret them.
Many have undertaken to draw up an account of the things that have been fulfilled among us, just as they were handed down to us by those who from the first were eyewitnesses and servants of the word. With this in mind, since I myself have carefully investigated everything from the beginning, I too decided to write an orderly account for you, most excellent Theophilus, so that you may know the certainty of the things you have been taught. (Luke 1:1-4, NIV)
In this passage, Luke is using the standard type of preface for writing ancient history. If Luke wanted his readers to recognize the story of Jesus as myth, he is starting his Gospel in totally the wrong way. Any ancient reader would look as this preface and recognize right away that Luke was attempting to write history.
The next passage is about John the Baptist.
In the fifteenth year of the reign of Tiberius Caesar—when Pontius Pilate was governor of Judea, Herod tetrarch of Galilee, his brother Philip tetrarch of Iturea and Traconitis, and Lysanias tetrarch of Abilene—during the high-priesthood of Annas and Caiaphas, the word of God came to John son of Zechariah in the wilderness. (Luke 3:1-2, NIV)
Luke introduces the ministry of Jesus with a description of John the Baptism. John and Jesus are so intertwined that you can’t have one being mythical without the other. Unlike most mythical texts, this story is not placed in the mythic past but rather is rooted in history. And not just history, but recent history. Luke’s Gospel is dated somewhere between 60-85. Even with the latest date, there are people who were alive during John’s ministry who were still alive when Luke was writing. Notice also the piling up of historical references. Luke is not just adding colour to his narrative, he is emphasizing the historical context in which both John and Jesus lived.
Does this prove that Jesus was a historical figure? No. But a careful reading of Luke’s Gospel suggests that he thought he was writing history and not mythology. If there was a Jesus myth, Luke didn’t know about it.