Natman I thought there were contempory accounts of Jesus as a historical figure outside of the Bible? As there are of Mohammed. Is the issue more to with divinity rather than existance?
As for Marc's 'Jesus was a creationist who believed Genesis 1-11 as history' argument-the first creationist that had a go at me seemed to use that as some kind of classic, clincher argument when I'd ripped to shreds his science arguments and those of his precious AiG book (which became a comedy classic down the pub)-initially as nicely and politely as possible, till he bacame nasty-then I moved to writing A level equations for the second law of thermodynamics and asking him to show me how they precluded evolution. Paul Taylor funnnily enough, used the same Jesus argument on his visit to Redditch Elim liars for Jesus.
Anyway when being told Hawking/Darwin/every piece of science is wrong by someone whose total knowledge of science could easily be written on a postage stamp and still leave room for the complete works of Shakespeare didn't work, the guy resorted, rather triumphantly to that argument.
Showing just how out of touch your average creationist, including Marc, is. People don't choose to believe evolution they accept the evidence. Evidence that is not only overwhelmingly in favour of it but simultaneously falsifies Genesis as literal six day history. So when this guy, (and Marc), uses the Jesus as creationist argument they don't seem to realise that what they are doing is arguing very strongly that Jesus did not understand any science at all.
When I told this guy that if he could prove Jesus a creationist beyond all shadow of doubt he would not be proving Genesis literal but Jesus not divine, he resorted to condemning me to hell, not unlike Marc suggests. But hey I went to an RC school, I was taught by nuns! I'd already gone thru and got over the nightmares about that one when tiny. In short the guy showed himself to be a total moron.
I didn't pursue or check the issue at the time because, contrary to popular creationist myths about atheism, I would like there to be a God, and I didn't want to rock the boat. It took a bit more exposure to creationists, culminating with Marc who finally clinched it for me, to move from believer to non believer.
So Marc if i were you, when faced with someone who understands anything about science, I'd keep the Jesus as creationist argument firmly under your hat. You've already created at least one atheist, I'm not quite sure creating more is exactly what your religion requires of you!!
