Post Author: Bill Pratt
I am aware that there are philosophers who employ Bayesian analysis to determine probabilities that historical events occurred, but I am becoming skeptical of the value of these analyses. A Bayesian analysis requires a calculation of the prior probability that a historical event occurred, without considering any of the evidence we have that the event occurred. But how we do calculate prior probabilities for a historical event?
I think the problem was clearly illustrated in a debate between Greg Cavin and Mike Licona. Cavin mounted an attack on the resurrection of Jesus by arguing against the prior probability of it. Remember that prior probability calculations ignore the actual evidence for the event. Here is Licona’s summary of Cavin’s argument (note: Greg Cavin has contacted me and denied that he made the argument presented below, so I have edited the comments below to represent a generic argument made by a generic atheist named Bob; even if Cavin did not make this argument, I have heard arguments like it made plenty of other times by other atheists):
[Bob's] first argument is the probability that Jesus rose is astronomically low, since, even if God exists, he doesn’t have a tendency to raise people from the dead. In support he said that, of the estimated 100 billion people who have lived and died on the Earth, the historical evidence is inadequate to suggest that any have been raised from the dead. So, even if the historical evidence for Jesus’ resurrection were good, there would still be only a 1 chance in 100 billion that Jesus was raised.
I replied that historians don’t use prior probabilities in historical inquiry. One cannot calculate the prior probability that the U.S. would drop nuclear bombs on Japan during WWII, since in all of human history no nation had dropped a nuclear bomb on another before or since WWII. Moreover, I’ll be 51 in two weeks. That’s a lot of days in my life. Yet Sunday was the first day I had ever spent in Temecula, California. Given my “tendency” not to go to Temecula, one should conclude that I wasn’t there that evening. Historians examine a historical report then look at the evidence for the event occurring. Thus, prior probabilities are the wrong tool for historical inquiry. It’s like using a calculator for an archaeological dig.