Why is the Historical Jesus Quest so difficult?

Mark Goodacre has an interesting post over at NT Gateway, summarising why the quest(s) for the historical Jesus is so tricky as 7 points

(1) So much data is missing, e.g. there is so little on Jesus’ life before 30.

(2) The data we do have is highly prejudiced, mainly pro-Christian propaganda.

(3) The sources we have are disputed -- different scholars value the sources differently

(4) The sources are sometimes contradictory and difficult to interpret.

(5) Our distance from the data is so great – we read our own prejudices into the texts.

(6) And now there is so much secondary literature available that it is difficult to navigate our way through it all.

(7) Jesus is a figure in whom so many have a stake, and the quest is often controversial.

These points are a mix of those that apply to any historical figure, and those that apply particularly to religious figures, or those whose ideologies remain controversial. However, with numbers 6 (the muddying of the waters by other questers) and 7 (the controversy), although they are not exclusive to Jesus, it's hard to think of a figure for who they could be truer. I'm guessing of course, but I imagine that more books have been written about Jesus than any other figure, and of course each of these has been distorted by these 7 points as well.

I'd also add an eighth - that there seems to be so little agreement. It must be very difficult to know what foundations to start building on, given that whichever foundation you start on will be rejected by more people than accept it. Obviously most people accept Jesus was a first century Jew, but beyond that there is such tremendous diversity.

Mark concludes that he will go on to tell his students that "the news is not all bad. We are actually surprisingly well informed about Jesus compared to many other figures from the ancient world". Which is true, and of course one advantage of his importance through the ages is that we have (relatively speaking) such old documents found and preserved.

One of the reasons that this summary is of interest is because I'm in the middle of a bit of a catch up session on historical Jesus literature at the moment. Having finally read Geza Vermes' "Jesus the Jew" over the summer, I've also recently finished Borg & Wright's "The Meaning of Jesus" (my thoughts on that can be read here), Crossan's "The Essential Jesus" which I hope to make a few rudimentary points on fairly soon. I've also (re-)read a few of the other documents outside the New Testament, such as "Q", Gospels of Thomas, and Mary, and the Infancy Gospel of James. I've also just acquired a copy of Crossan's "The Historical Jesus", and find myself wanting to re-read Wright's "Jesus and the Victory of God", as I've forgotten most of what I liked about it last time (other than what I've read of his elsewhere). Perhaps it's about time I re-read some of Mark's old lecture notes as well.