Bayesian probability and God

Thomas Bayes was an 18th century mathematician, philosopher and Presbyterian preacher.  In what has become a pretty popular concept even in biology (I remember when I was interviewing for faculty positions four years ago a chair of an oncology department at a university in Boston asked me what I thought about using Bayesian probability to develop cancer treatments, and I deflected for a couple obvious reasons) I came across an interesting use of Bayesian probability by Don Page, who is considered by people in the field to be one of the top theoretical physicists in the world (and got his Ph.D. under Stephen Hawking).

Page, although its clear not the reason he is a Christian, uses Bayesian probability to justify his belief in God, and specifically the Christian God. Bayesian probability is a system of probability that incorporates traditional measurements of probability (frequency and chance) with components of propositional logic, to form a system where proposition and hypothesis can be combined with frequency and chance. This can in turn be used for things like what are the statistically best cancer treatments for a cancer when much of the figuring out which treatment is best is based on uncertain hypothesis, or, as Page uses it, for a worldview.

Page reasons it out something like this: Given even just a low probability that an intelligent Creator is responsible for our universe and us, the historical evidence of Jesus Christ and the Resurrection event moves it from the overall chance for God from a low probably to a high and very likely probability.

It is obviously completely devoid of any philosophical arguments for God, and as such, is catered towards those inclined to think about God in purely mathematical terms. I personally believe that it is warranted (as I have written about) to consider belief if God a, as Alvin Plantinga would categorize it, proper belief (a belief that needs to be assumed to make sense of anything, in particular sense itself), but that will not satisfy many, not even the most open-minded. I also believe, as you would imagine, that de novo the chance of God (meaning an intelligent Creator) is very high, as I think at this point of our understanding a matrix-like reality is the only plausible alternative to a reality created by an intelligent Creator. But to the credit of Page, he has assigned a very conservative value to the existence of God, and put the onus on the evidence of Jesus and His Resurrection as the major probability mover. And I like that. It also forces anyone taking Page seriously on this to take an equally serious look at the evidence for the Resurrection and genuine start of Christianity (as I’ve noted in the past, a thoroughly convincing case is laid out in N.T. Wright’s “The Resurrection of the Son of God”). I believe this is where the real strength of this approach is, from an evangelical standpoint. This will hardly matter for hard and ardent atheists who have fully closed their heart to the possibility of God (which, as I’ve said in the past, has nothing to with the reasons, per se, for God, but like all of us, are highly influenced by other factors). But for those with open minds and hearts to the possibility, it very well could turn the tide. And that is what good evangelizing is: gentle, respectful, genuine urging to share in the greatest story every told; which just happens to be true.