Atheist YouTuber and “Street Epistemologist” Douglas Letkeman invited me to do a live conversation online this past Monday night. We talked for an hour and 45 minutes! Over 100 people joined us in the live chat, including half a dozen of my logic students. The conversation centered on what Doug calls “the Library thought experiment”– an exercise aimed at sniffing out inconsistencies in a person’s epistemology, that is, in the way they respond to evidence.
The Strange Library
The thought experiment invites you to imagine a strange library, where you work shelving new books. A new book arrives, and you are tasked with shelving it, but you may only look at a single page. The title, author, etc. are all hidden. On the single page you read, there is an account of a man who runs off a cliff and flies through the air like Superman. So where do you place the book? In “history” or in “fiction?” You will probably assign it to the fiction section, presumably because you don’t believe this event actually happened.
Now suppose you read another random page, and the book claims that more than 500 witnesses saw the flying man fly. Still fiction? Suppose a third page reveals a “creed” that was recited by believers in the flying man, written soon after his amazing flight. Are you now inclined to think this is a true story? A fourth page asserts that many of the witnesses died because of their belief in the flying man. Is this enough to convince you that the flight of the flying man was an historical event?
You see the parallel. The account and support for the flying man is supposed to be analogous to the account and support for the resurrection of Jesus. Doug’s view is that since they are analogous, you should treat them the same: if you believe in the resurrection, you should also believe in the flying man. But Doug also assumes that most of us would find the flying man story to be rather unbelievable. And if this is so, then you should also be skeptical of the resurrection of Jesus.
In the video, we talk about the thought experiment and these parallels in great depth. If you don’t have time to watch it, here’s the executive summary. As Doug added on each bit of evidence for the flying man, I said that my confidence in the truth of the account shifted toward belief. However, after 5 or 6 items of evidence for the flying man, I didn’t yet feel that the case was strong enough to warrant belief. Similarly, if I had exactly the same 5 or 6 fragments of evidence for the resurrection, I would probably not believe it happened. I would be right on the threshold between “undecided” and “belief.” I would need additional evidence to propel me through the door.
Thankfully, the case for the resurrection of Jesus contains that additional evidence. One of the additional items is the coherence of the narrative surrounding the resurrection–there is a clear purpose for the event and it fits into a coherent, broader story. Another is the presence of genre clues embedded in the text. The authors of the gospels wrote in the style of ancient biography, not poetry or myth. We could go on: the empty tomb, the first witnesses being women, etc.
The Cumulative Case
Doug also wanted this to be an argument against the “cumulative case” defense of Christianity. The cumulative case approach goes something like this: no single argument or bit of evidence for Christianity is sufficient to warrant belief, but all of them together are sufficient. I think this makes good sense. But Doug wanted to use the Library story to somehow undermine it. I never quite understood how that was supposed to work. The Library case just shows that you shouldn’t believe an unlikely story based on one bit of evidence. But what if you have many bits of evidence?
To show how the cumulative case strategy works, consider a murder investigation. A detective may begin with several suspects and a few items of evidence. One person saw Mr. Smith near the crime scene on the night of the murder. Should the detective believe that Smith is guilty based on this one bit of evidence? Of course not. But over the course of the investigation, the detective uncovers more and more evidence that Smith is the murderer. It becomes increasingly unlikely that all these bits of evidence are coincidence–Smith looks more and more guilty. Eventually, there is sufficient evidence to arrest Smith and prove his guilt. No single item is sufficient, but the total package is. The detective is using a cumulative case approach.
One objection I’ve heard is this. If each individual item is weak or bad evidence, then no matter how many you add up, it won’t be sufficient for belief. Well, if the items are just weak on their own, then this is exactly what the cumulative case says. Any single column of a cathedral is too weak to hold up the roof. But this doesn’t mean that a collection of columns couldn’t do the job. This is, in fact, how architecture works.
But what if each item is bad evidence? A fairly standard definition of evidence is “anything that raises the probability of the hypothesis.” So, if by ‘bad’ we mean that the item does not raise the probability that the resurrection account is true, then I agree. But each of the items I discussed with Doug would, if true, raise the probability that the resurrection occurred. One may argue that one or more of the evidential claims is itself false, but that is a completely separate discussion. Needless to say, one can’t simply dismiss them as false without argument. Near universal agreement among liberal and conservative scholars alike supports many of them, such as the fact of the empty tomb, or that the disciples claimed to have seen him alive.
So, I don’t see how the Library thought experiment undermines the cumulative case strategy. In fact, it seems to illustrate exactly how it works. Start with one item of evidence, and continue to add more until you have enough for justification. It isn’t easy to say how many items that would take (a discussion for another time), but surely it is finite. My faith, and the faith of many people I know, rests securely on a collection of sturdy “columns.”