Before we question whether the miracles of Christianity happened, in this episode we question whether miracles in general can happen. We look to David Hume, black swans, and Bayes' Theorem.
Bayes' Theorem, for those who really want to know:
Pr(M|E&B) / Pr(not-M|E&B) = Pr(M|B) / Pr(not-M|B) x Pr(E|M&B) / Pr(E|not-M&B)
Translation of equation:
Probability that a miracle occurred = Probability of a miracle given our background knowledge divided by the probability of not a miracle given our background knowledge times the probability of the evidence for the miracle given the miracle occurred and given our background knowledge divided by the probability of the evidence given that the miracle did not occur and given our background knowledge.
Whew... Or, another way to think about it:
The probability that a miracle occurred is a factor of both the intrinsic probability of a miracle and the explanatory power of a miracle to account for the supposed evidence for it.
Or, just google it.