How well do the much-touted similarities of the Jesus story to other myths hold up?

[whatthehey]

23. Depends on how you want it to "stand up"

There are many common tropes in the Jesus story that could easily have been integrated onto local folk tales. The risen hero. The poor savior. The noble sacrifice. But these will only persuade people who already understand them and how folk literature develops in the first place. It's easy for such people to see parallels between, say, Jesus and Osiris or Zoroaster, but the simplistic audience fixates on disparate details. Remember there are many people who do not get the parallel between Romeo and Juliet (itself utterly unoriginal BTW) and West Side Story because there are no singing streetgangs in the former. Osiris lost his penis! Zoroaster wasn't the son of God!

There is probably more fertile ground with a believing audience in restricting criticism to the Jesus myth itself and not having to rely on external knowledge of folklore arcana. How his life story becomes more embellished and more divine from earliest gospel Mark to latest John. How it is an amalgam of Jerusalem and Galilee traditions. How the very first christological writings from Paul barely acknowledge a living human messiah at all. If they are likely to be persuaded by other source parallels it may be better to start with the numerous hagiographies of other would be Messiahs that abounded in 1st Century Palestine like Grisham novels in 21st Century JFK, and how several of these featured the same character as the scriptural Jesus flying like Superman, killing childhood pals (it's ok, he raised him again) and acting more Marvel than Mishnah. If they can handle that it's only then worth much effort talking about basic hero-myth themes and how Jesus suspiciously ticks all the boxes.

As far as historical corroboration goes, only an idiot believes the bit in Josephus is genuine and original, and just about all other non-biblical historical references even close to the same time mention not the man/god but his followers. There are many very accurate current writings about MUFON. It doesn't mean MIB is a documentary. The only even vaguely convincing bit is Tacitus, written about 75 years after. Tacitus was a good historian for his time, not a Herodotus-like tale-spinner, but he makes a mistake in the very same passage about Pilate so he's not infallible, and in any event is merely relating who the Christians are, and in doing so gives their origin story. It's the equivalent of us saying something like "Muslims greatly revere Muhammed. who listened to the Angel Gibreel and wrote the Koran". We are not saying that Gibreel really exists let alone dictated stuff to a medieval Arabic merchant. We are saying, accurately, that's the figure whom Muslims revere, and for that reason among others.

To be fair though it's straining credulity to assume whole cloth fiction too. These were not the times of googling or video evidence, and religious and superstitious ferment was widespread, but even so we do know, unquestionably, that people who were adults when he was supposed to have lived were willing to be killed for saying he was at least a prophet of God if not God incarnate. To be sure even in this age we have Moonies and Davidians and Schneerson-as-Messiah Chabadis, but all those leaders, surely mortal all, actually existed. Even then it's hard to imagine such a strong following built around somebody who never drew breath at all.

The TLDR version. There is little to no unbiased corroboration he existed, and we can say nothing positively true abut his life at all. The miraculous stuff can be dismissed out of hand (we have tanners' price lists from that milieu; if the dead rose from their graves when he was crucified, or if a king, who BTW died in 4 BCE, had slaughtered an entire cohort of infants, there'd be some mention of it). There are numerous both detailed and themic parallels with other hero myths and clear evidence of massive rapid embellishment, but there in all probability was some charismatic preacher around whom those myths and embellishments coalesced, but about whom we know bugger all for sure.