Historians can only establish what most likely happened in the past, based on the material and literary evidence we have. So let’s build the case:
We don’t have material evidence for the resurrection (Sorry, the Turin shroud doesn’t count), but we do have early Christian accounts: comments of Paul (the earliest texts) and the narratives of the Gospels (of which Mark is probably the earliest), and we have later christian accounts as well, but they are all dependent one way or another on these – let’s say – canonical versions.
Regrettably (speaking as an historian), these canonical accounts come many years (at least decades) after the events described, and they are written by people who were not there (time/place) when the Resurrection (supposedly) took place. They base their stories on oral reports circulated; Furthermore: the biblical accounts are not “disinterested” – All authors are deeply committed to the belief Jesus wàs raised. And even though they agree with much of the gist of the story, they contradict each other repeatedly, in detail after detail. So the basic questions: who, what, where, when, how etc… don’t get an unequivocal answer. These are not the kinds of sources that historians normally find reliable.
But for the sake of the argument, we’ll accept that there is a case.
This brings us to the central question. Given the reports that Jesus was seen alive after his burial (these reports are ‘facts’ and make the case), a historian must weigh which explanation best explains how these stories first emerged. A matter of ‘probability’.
Is a physical resurrection the most probable explanation? And I mean, not for “belief” but for straight-up regular oldskool “historical investigation”. Otherwise put: Is a one-time act of God more probable than the possibility that people did ‘see’ Jesus (the vision is a fact) and took their vision for reality, or that they felt Jesus was present, and then embellished the stories, or that people who said they saw Jesus were simply mistaken, or that rumors were started (vague, imprecies) and then widely spread, were exaggerated in one way or the other? Just in terms of probability – is there anything inherently improbable about these explanations? People seeing things that are not really there, embellishing stories, misinterpreting what they saw, repeating and distorting rumors? Not really. It happens all the time. On the other hand, how often does it happen that someone is truly dead (not in a coma etc.) and is actually restored to life days later and then is ‘gone’.
Weird things happen, yes, all the time. But laws of nature do not get broken all the time.
As I stated at the outset, I am not arguing Jesus was not raised from the dead. I am arguing that believing he was is a matter of faith, not of historical demonstration.