Not long ago, one of the IT staff who was in my office to sort out access to the new network on campus asked me if my research often came into conflict with my faith. He was killing time waiting for some process or another to work through and making polite conversation. :-)
As a result of my work on memory and eyewitness testimony, I am more firmly convinced than ever that we are never going to be able to prove that we have access to the authentic words of Jesus. I don’t see that this actually matters a great deal from a faith perspective, although it should have a significant effect on how we do our exegesis.
I am a fan of detective stories and TV shows and as such am well aware of the importance of having an alibi for the time of a crime if you want to be removed from the list of suspects. I am also aware that there are significant portions of most of my days when I would not be able to provide an alibi if I were accused of a crime because my office is fairly isolated and once the door is shut to keep out the cold or the heat, no-one knows whether or not I’m there. Because I connect to the internet via my laptop, the fact that I’d sent and received emails wouldn’t prove my location, either, just that I was somewhere on campus, I think. The fact that I can’t prove that I was in my office doesn’t make it untrue, but whether or not people were prepared to believe me would depend on my track record for honesty in the past and they would take into account whether I had an obvious motive for committing the crime and for lying.
At home, if I say to my son “Did you use the last of the grated cheese and not put it on the shopping list?”, his reply is most likely to be “You can’t prove that!” And, of course, unless I or someone else was watching at the time, I can’t. If there was cheese in the fridge fifteen minutes before and he was the only one in the kitchen, it’s highly probable that he was the person responsible. If it’s been several days since I last saw cheese in the fridge, any member of the family except the puppy could have done it, but he is the most likely person because he uses the most grated cheese and is more prone than his sister to not put things on the shopping list. His father is also not so good at putting things on the list, but doesn’t use grated cheese except under extreme duress. I am not perfect about putting things on the list, either, but I would almost certainly remember having used the last of the cheese when I went to get some more. Also, my son usually only says “You can’t prove that!” if he’s responsible for the thing he’s telling me I can’t prove. I can therefore say that even though I can’t prove it, on the balance of probability it’s true.
I think that this is the best we can hope for in biblical studies (or any study of historical events that took place before the advent of modern technology) – until such time as someone produces a machine capable of time travel and miniature recording devices that are not visible to those being observed, anyway. Furthermore, our assessments of the likely reliability of particular sources of information is fairly subjective, so we aren’t going to agree totally on what deserves the “balance of probability” vote. The fact that I can’t prove something doesn’t mean that it isn’t true, though.