One other thing that Ehrman says is that those gods alleged to be dying and rising gods, such as Osiris and Dionysus, were
not in fact dying and rising gods. This seems to be a view that is now in fashion. I'm in the process of reading a review copy of Burton Mack's latest book, in which, in passing, he makes the same assertion. Among objections to seeing Osiris as a dying and rising god is that the risen Osiris only reigned in the underworld, the land of the dead. Ergo, he was not resurrected to life. This ignores the fact that Osiris wasn't just killed by his brother Set, but was also chopped into 14 pieces. Isis, wife of Osiris, collected them, reassembled the body of Osiris and physically resurrected him. He lived, then, albeit in the underworld.
We would naturally expect the Christians in adapting the myth of the dying and rising god, would have changed and possibly improved the story. It's also simplistic to assume that the Christ myth was
entirely based on pagan dying and rising gods. The narrative material of the gospels is derived from four separate sources. These are: pagan myth, Greek literature, Jewish apocalyptic belief and the politics of the day as seen in apocalyptic terms, and the Jewish scriptures.
The "anti-mythicist" view seems to see the Jesus as a dying and rising god as the invention of of late nineteenth and early twentieth century writers, such as Frazier. However, such a view ignores what the second century Christian writer, Justin Martyr, wrote in his
First Apology, addressed to Emperor Antoninus Pius. In
chapter 21, Justin give all sorts of analogies between Jesus and pagan deities / heroes of classical myth. Also, in chapter 54 Justin attributes that the similarities between Christian and pagan belief to the work of devils corrupting a prophecy of the Christ made by Moses (emphasis added):
The devils, accordingly, when they heard these prophetic words, said that Bacchus was the son of Jupiter, and gave out that he was the discoverer of the vine, and they number wine [or, the ass] among his mysteries;
and they taught that, having been torn in pieces, he ascended into heaven. And because in the prophecy of Moses it had not been expressly intimated whether He who was to come was the Son of God, and whether He would, riding on the foal, remain on earth or ascend into heaven, and because the name of foal could mean either the foal of an ass or the foal of a horse, they, not knowing whether He who was foretold would bring the foal of an ass or of a horse as the sign of His coming, nor whether
He was the Son of God, as we said above, or of man, gave out that Bellerophon, a man born of man, himself ascended to heaven on his horse Pegasus. And
when they heard it said by the other prophet Isaiah, that He should be born of a virgin, and by His own means ascend into heaven, they pretended that Perseus was spoken of. And when they knew what was said, as has been cited above, in the prophecies written aforetime, Strong as a giant to run his course, they said that Hercules was strong, and had journeyed over the whole earth. And when, again, they learned that it had been foretold that He should heal every sickness, and raise the dead, they produced Æsculapius.
I suspect that we will have to weather the idea of dying and rising gods being out of fashion for a number of years, after which the idea might well be in vogue again. I'd be interested to hear what either Ehrman or Mack have to say about the words of Justin Martyr.