Other people have pointed out the problems with singling out Christianity and ignoring a lot of disjoint possibilities. As to your question, someone on another site named a level of evidence that feels like it would make me consider deities as explanations. Representatives of a deity (or the deity itself) would need to publicly create specimens of a species believed extinct. They would need skeptical observers, well-versed in stage magic, to declare themselves baffled. And then they'd have to hand the specimens over to skeptical biologists for another kind of confirmation. This level of evidence feels like it would bring my belief in some deity's existence to more than 1%. (ETA: but see the dream thread.)
Now for "the chance that Jesus of Nazareth is a resurrected God", it would take all that plus additional evidence on the level of the following: Christians moving mountains through faith alone, plus a persuasive-sounding explanation of why I haven't observed this happening before. That seems like it would bring my credence above 1%. Though now that I've written this, .01 feels possibly too high to be internally consistent.
A friend recently asked how strongly I believe that my deconversion from Christianity was not a mistake. Here's my response, and for those of you who are not Christians, I'm just wondering what numbers you would give:
"There is a part of me that wants to say the chance is far less than 1 percent. But when I consider what 1% must mean about my ability to follow complex arguments and base my judgement on the right premises, it seems absurd to say that.
Trying to honestly estimate the chance that I'm wrong about the Bible being generally reliable is a fascinating exercise... I know the number is low, but I'm not sure how low.
Today I would give myself a 1 in 20 chance of being wrong. If I were to consider the arguments of 20 other groups similar to Christian theologians, I would probably misunderstand them at least 1 time in 20. After talking with 20 groups that have a very different worldview, I might think they are all are mistaken, but once in a while, maybe 5% of the time, it would actually be me.
Wow, 5%!?! If I convert that into "There is a 5% probability that the God of the Bible exists and will send me to hell", I feel scared. But I know how to cheer myself up: I just say, "No way, the chance I'll end up in hell MUST be less than 5%. After all, the God of the Bible is CLEARLY just a big, mean alpha-monkey and... [rehearse all the atheistic arguments here]".
This back-and-forth from certainty to uncertainty makes me feel like I'm doing something seriously wrong.
So what about you? What chance do you place on some variant of Christianity turning up to be true, and what chance do you think a god of some sort exists?"
Numbers please.