We might start by remembering that no evidence, ordinary or otherwise, can prove any claim in a mathematical sense. Facts about empirical reality can never be established to that level of certainty. We can justify what we believe, but we can never with perfect certainty rule out the possibility that we are mistaken.
We can get close, though. Broadly speaking, evidence for a claim is a set of facts that justifies belief in the claim. The facts justify the belief if they logically imply, to some significant level of probability, that they are inconsistent with the falsity of the claim. The higher that probability, the stronger the evidence is said to be; and if the probability approaches certainty, then we may say the evidence is conclusive.
But conclusive evidence can be quite ordinary. A corpse, whether or not it can be identified, is conclusive evidence that somebody has died, but there is nothing extraordinary about a corpse.
Now, the claim "Somebody died" is itself pretty ordinary in the usual sense. As far as we know, death happens to everyone. Also as far as we know, it is always permanent, at least for humans and other mammals. People who do die stay dead, without exception.
Such is the common experience of humanity. All people have witnessed death. Almost no people have witnessed any dead person returning to life. That "almost" is necessary because there are people who claim to have seen at least one dead person return to life. Those people are very few, but they exist.
And, their testimony is evidence of something. But of what?
Mistaken or dishonest testimony is also part of humanity's common experience. We are all subject to error in our perceptions and memories, and we all know that. Some people also tell lies. We all know that, too.
It is also part of common experience for people to tell stories that they know are not true but don't expect anyone to believe. We call these stories fiction. They are usually told primarily for entertainment, but they are sometimes intended also for enlightenment of some kind.
It also sometimes happens that people who hear fictional stories believe they are hearing factual history. Therefore, while testimony of a resurrection could be evidence for a resurrection, it could also be evidence for any number of other events. Other relevant facts might help us decide how best to account for the testimony's occurrence. I propose now to define an extraordinary claim as one that is inconsistent with well justified beliefs based on the common experience of humanity. Let us call the those beliefs conventional beliefs. I then suggest that the evidence required to support such a claim should be sufficient to falsify those conventional beliefs. Such evidence would be a set of incontrovertible facts that are logically inconsistent with our conventional beliefs and therefore compel the inference that those beliefs are untrue. If it can be demonstrated by a cogent argument that the facts in evidence are inexplicable except by supposing that the conventional beliefs are wrong, then we have our extraordinary evidence. But if the conventional beliefs can explain the evidence, then the evidence is not sufficiently extraordinary to support the claim.
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