Here is an argument that I present and examine in my paper “Evidence, Miracles and The Existence of Jesus”, published in Faith and Philosophy, April 2011. Volume 28, Issue 2. Pages 129-151). The defence of premises P1 and P2 is in the paper, which can be viewed here.

William Lane Craig’s response is here.

In the paper, I make a case for being sceptical about the existence of Jesus (though I am no less scepticial about the mythicist position). The paper challenges the consensus among Biblical scholars and historians that the existence of Jesus has been established beyond reasonable doubt.

1. (P1) Where a claim’s justification derives solely from evidence, extraordinary claims (e.g. concerning supernatural miracles) require extraordinary evidence. In the absence of extraordinary evidence there is good reason to be sceptical about those claims.
.
2. There is no extraordinary evidence for any of the extraordinary claims concerning supernatural miracles made in the New Testament documents.

3. Therefore (from 1 and 2), there’s good reason to be sceptical about those extraordinary claims.

4. (P2) Where testimony/documents weave together a narrative that combines mundane claims with a significant proportion of extraordinary claims, and there is good reason to be sceptical about those extraordinary claims, then there is good reason to be sceptical about the mundane claims, at least until we possess good independent evidence of their truth.

5. The New Testament documents weave together a narrative about Jesus that combines mundane claims with a significant proportion of extraordinary claims.

6. There is no good independent evidence for even the mundane claims about Jesus (such as that he existed)

7. Therefore (from 3, 4, 5, and 6), there’s good reason to be sceptical about whether Jesus existed.

Notice that this argument is presented in the context of a discussion of what it is or is not reasonable to believe on the basis of the historical evidence.  The argument combines P1 and P2 with three further premises – 2, 5 and 6 – concerning the character of the available evidence. These are the premises on which historians and Biblical scholars are better qualified than I to comment.

Clearly, many historians also accept something like 2 and 5. A significant number remain sceptical about the miracle claims made in the New Testament, and so they, at least, are clearly not much tempted by the Presuppositions Move outlined above (which involved the suggestion that, for those coming to the evidence with Theistic presuppositions, the New Testament miracle claims need not, in the relevant sense, qualify as “extraordinary”). Michael Grant, for example, says: “according to the cold standard of humdrum fact, the standard to which the student of history is obliged to limit himself, these nature-reversing miracles did not happen.” . What of premise 6? Well, it is at least controversial among historians to what extent the evidence supplied by Josephus and Tacitus, etc. provides good, independent evidence for the existence of Jesus. Those texts provide some non-miracle-involving evidence, of course, but whether it can rightly be considered good, genuinely independent evidence remains widely debated among the experts.

So, our empirical premises – 2, 5 and 6, – have some prima facie plausibility. I suggest 2 and 5 have a great deal of plausibility, and 6 is at the very least debatable.

My suspicion is that a significant number of Biblical scholars and historians (though of course by no means all) would accept something like all three empirical premises. If that is so, it then raises an intriguing question: why, then, is there such a powerful consensus that those who take a sceptical attitude towards Jesus’ existence are being unreasonable?

Perhaps the most obvious answer to this question would be: while many Biblical historians accept that the empirical premises have at least a fair degree of plausibility, and most would also accept something like P1, few would accept P2.

I’ll provide the argument for P1 and P2 in a separate post.