Oh, yeah, it's incredibly dodgy. If you want to go ahead and question dogma and all, that's good and fine, but it's best to do it in reputable, scholarly ways, and not by using theories outdated and disprove for over a hundred years (note that the idea that many aspects of myth go back to the 'sun' and the 'zodiac' was a very old theory for the purpose of myth, oh, some hundred and fifty years ago. Not in particular regarding Jesus, but, say, Greek myth. It was mostly discredited when people began using the same logic to 'prove' that Napoleon's twelve marshals didn't exist. This comment regarding this zodiacal theory I ran across quite seperately and on an unrelated note, whilst glancing through a book on Indo European myths.) The point is, if you want to be skeptical about the validity of the 'history' of Jesus, fine. There's not really anything 'factual' we can say about it (unless you want me to bring up Aristotle's comment in the Poetics where he says that 'poetry is something more scientific than history because history only tells us specific facts, whilst poetry tells us general truths.') Anyway, beyond some offhand references by Tacitus, who hated Christians apparently, and similar Roman historians, there's really nothing for the actual existence of Jesus other than the canonical manuscripts. Those are, from an objective opinion, the oldest mentions we have (nb. that the canonical works are, by and large, a good hundred years older than the material considered marginal like the Gospel of Judas and the Gnostic works... believe what you will, therefore, but what is considered canonical Bible is the oldest stuff we have from the era, that written closest to the time.)
Now, there's a lot of things I can say to 'debunk' this Zeitgeist thing. I think all that one must say is that it is absolutely absurd to me and, at any rate, they simply make things up. No, I have never even heard of any 'virgin birth' story regarding Horus. He was, in fact, the son of Osiris and Isis... Isis being pretty well the Egyptian Aphrodite. Now, if you want to call Aphrodite a virgin... well, you can see this is taking a rather strange turn. Plainly they are simply making things up in regards to the ancient myths, and that lack of even basic scholarly knowledge throws the most of it into great disrepute. That they so strongly attest to a virgin birth for Dionysus, as I think it is... he was a 'twice-born' god, true; one could make an argument that an aspect of him is connected to 'resurrection' myths, true; but that he's some kind of Jesus figure? Ridiculous (except for that resurrection bit... there you can make some vague connection... but considering that there are a thousand other resurrection myths, it's more apt to place Jesus into a broad cultural category of story featuring the concept of rebirth.) Even worse is that these supposedly 'earthshaking' theories are, well, hundreds of years old, and were in fact shown to be entirely un-scholarly many, many years ago. No scholar on the matter would ever consider anything of this to be remotely telling of anything. And this isn't speaking dogmatically at all. If someone made this sort of theory about the Greek myths I'd think the same (well, as I said, they did, and a hundred years ago it was laughed out of academia... strange that it's been brought to bear now regarding religion, and the masses are taking it to be something profound.)
And far the worst... they do miss the one major 'archetype' character for Jesus: Socrates. I'm quite certain that those writing the Bible in Greek were well aware of the Socrates tale, and modelled something of Jesus after that. They both have this 'great teacher' aspect, who has deciples; who is looked down on by the ruling authorities; who is killed by the ruling authorities; who teaches his disciples not to fear death, and that there is more than this world; and whose students carry on his work. There's a great deal of typological similarity between Jesus and Socrates... yet that, something that one could actually make a good case for is overlooked in favour of this sensationalist dribble.
So don't worry. Most of their 'facts' aren't anything near to that. Far worst of their flaws are those pertaining to the ancient myths (which I do have quite a bit of knowledge regarding.) And if you want to see the entirety of their flawed logic, just looked at their 'cross' explanation. Why in the bloody world is that a simpler explanation than, well, condemned criminals under Rome were crucified. Uh, I think the connection there is pretty obvious. To argue that it comes from a circle-cross shape... is simply ludicrous, especially when that 'halo' is only a figure on Celtic crosses from almost a millenium later! Yeah, there was some connection between sun cults and Jesus... I think Constantine made a deft political move in that. But that it sprung from that? Absolutely nothing to substantiate it.
Oh, and furthermore, and here I'm rambling about their entire uninformed 'thesis'... supposedly Moses represents the age of the Ram countering the age of the Bull... yet if their numbers are right... 2000BC? I highly doubt Moses was contemporaneous with Middle Kingdom Egypt. Moses lived roughly 1300BC, almost 700 years after the mark they set. If you want to make a more coherent argument you might say that rams represent a nomadic people, whereas bulls are more of a settled folk... thus the enternal struggle in old Hebraic culture between nomad and settler, which might even be seen in the story of Cain and Abel. That's a valid thought, if you want to put very base symbolism into it (though such direct symbolism is more a product of our crude modern thought and usually doesn't apply well to antiquity.) And, heck, I looked up once the Zodiac on Wikipedia, eh? Guess what... it was founded under Zoroastrianism I think... something like 800BC... far, far too late for the time frame they're talking about. I suppose if you late-date the writing of the Pentateuch (it is possible) that can be considered, but it's really too great a leap in logic to be reasonably considered.
So in short... if you want to doubt our culture's myths, go right ahead: but have a valid argument to back it up. These people don't even know the first thing they're talking about. They sound like tabloid readers and wikipedia learners. They mix up time periods and theories of myth with wild and silly abandon and, amidst the confusion, think they've hit upon something profound. They think they're doing some 'deep questioning', but it doesn't take even half a mind to throw up some wild theory and apeal to people's sense of conspiracy... a classic rhetorical, and fallicious, mistake... dont' fall for it. If you really want to look at the propogation of myth, I'm sure there are a hundred good books on the subject written by reputable, peer reviewed, scholars. Take that over this sensationalized garbage any day.
For example, I began reading a book on how the God of the old Testament is often portrayed in character similar to the Cannanite war-goddess Anat (ie. which in Greek is Athene.) That in itself is an interesting thought to take on the matter. It's not nearly so emotionally appealing to the masses, it's true, but is something of good, sound, scholarly consideration, with cited sources (note, Zeitgeist cites no sources... not even having one of those token 'historians' which feature on some shows.) I'm also sure there are many good scholarly considerations of Gnostic works... after all, those have been around an in academic hands for thousands of years. But suddenly the Gospel of Judas came out and people got all 'ooh' and 'ahh.' Why, praytell? It was nothing new. Gnostic works like that had been about for ages. But it just wasn't, well, sexy. That's what that sensationalizing of it did through the media. It dressed it up into a big deal, because the tried and true academics and scholarly work of it just isn't enthralling to most people. So they take something that, to those who work in the fields, is rather old stuff, and dress it up like some new, wonderful discovery. Or worse, like this Zeitgeist, they take nuggest of fact and idea and wind it up in such confusing garbage and misinformation (with the token cheesy 'conspiracy' music in the background) so as to appeal to the weak emotions of the rabble. Don't let yourself get drawn into that. If you really are curious about this sort of thing, like I said, I'm sure there are plenty of true scholarly works dealing with the subject. Thought is the historian hereabouts... he might even be able to recommend some.
