Essay:Matt and Blake and Bayesian Analysis Letter

Hi Matt.

I am a massive fan of yours and I think that you are the best atheist debater in recent years. Blake Giunta is also a formidable debater and I like the clarity of his arguments (even though I think he's wrong).

However, if I can, can I offer some advice on tackling bayesian arguments.

There are many ways to look at the world. Bayesianism (if that's a word) is one of them.

However, it can be shown mathematically that bayesianism works: Any gambler who uses an alternative to it cannot rationally expect to do better. If blake giunta suceeds in showing that bayesian analysis makes theism more likely than not, he suceeds in showing that theism is more likely than not.

That is why it is very important that you engage with him head on and show him clearly that bayesian analysis does not make theism likely.

There are exactly two ways to do this: You could show that the prior is low, or you could show that our data is less likely under theism than atheism.

To show that the prior for the Christian God is low, there are lots of ways. One is to point out that you could easily imagine a million different gods or ways that the universe came about, and you don't see why any should be more likely than the others, and that's if there is a personal, human-like God who cares about us, so you could agree with Blake that you need a prior but the prior should be about one in a million.

Blake then tries to show that bayesian analysis then boosts this probability by only presenting evidence *for* the christian god. You can undo this by doing the opposite. For instance, ask him what the probability of a perfectly good God making a few percent of the world's population homosexual and then giving the rest of them a holy book telling them to treat them like sh*t? The answer is pretty f'ing low. What is the probability of a perfectly good God choosing to give his message through a first century religious cult? Pretty f'ing low. What is the probability that God would command his son to only speak in cryptic parables? Pretty f'ing low.

So to bring this together, we take the prior, which we agreed was perhaps one in a million. Then we add three "pretty f'ing lows" and we get a probability for the christian God that is pretty pretty pretty pretty f'ing f'ing f'ing f'ing low.

Please take this as friendly advice from someone in awe of your debating skills but who does understand probability theory well.