Doulos, your courtesy is appreciated. Dexter expresses a very reasonable frustration, that science generally finds it incomprehensible that people believe things that are simply false. You assert that Luke's claims to be writing history constitute evidence. Yet Luke wrote generations after the supposed time of Christ, and derived his historical fables from Mark. If Jesus was real, and not a myth, it defies credibility that the "evidence" is so late and so embedded in texts whose primary objective is to inculcate religious belief.
It defies modern standards of evidence (in a technological CNN world). The Gospels and letters of the New Testament were products of a primarily oral culture. They were set to papyrus beginning in the lifetime of Jesus' contemporaries (Mark is considered the earliest gospel with dating probably around 30 years after Jesus' death. Later dating is based upon a disbelief in the possibility of prophetic writing.) They thus reflect an already existant body of belief (sometimes called the hypothetical Q gospel), which was in circulation well prior to the time of writing.
I'm not sure what you're terming 'two generations,' as Luke is generally accepted as written in the early 60s, and so again in the lifetime of Jesus' contemporaries. His Gospel obviously derives some material from Mark, but adds detail as well. This detail was most likely already in circulation, and again could be varified by the still living witnesses, critics, and disciples of Jesus.
The fact that it was designed to inculcate belief is obvious. This does not denote falsehood though, merely personal conviction.
A lot of current research argues that the actual evidence is far more compatible with the invention of Christ than with the supposed 'big bang' of expansion of Christianity from a single historical founder. Paul barely quotes Jesus, and then only in ways that suggest a cultic archetype rather than a real person. The supposed external evidence such as from Josephus is blatant fabrication. Writers such as Philo who would have written about Jesus if he was real are silent. Earl Doherty's Jesus Neither God Nor Man presents a comprehensive logical and evidentiary demolition of the Historical Jesus hypothesis.
I think you're a bit out of date with this assertion. There was a period when it was fashionable to assert theories of Jesus' non-existance. That view has basically lost ground as critical scholarship has tested the theories. Even liberal agnostic/atheist theologians like Ehrman now accept the reality of Jesus' existance.
I'm not sure where you're getting the idea that Josephus is unreliable. There are about four passages from Josephus which are possibly modified, but this modification is mainly in degree (based upon Syraic desert copy of Josephus and scholarly critique). The fact that he wrote about a historical Jesus has never really been in doubt by mainstream academia, and Josephus is still regarded as one of our primary sources for his period. Which Philo are you referring to by the way, and why do you think he would hae written about Jesus?
I'm afraid I can't comment on Doherty's book, as I haven't read it. If you'd like to post some of his more convincing theories, I'd be happy to discuss them with you.