I was listening to the Unbelievable podcast today, which consisted of a discussion between AC Grayling and Peter S Williams on the topic of Grayling's new book: The God Argument. The book, incidentally, is sitting on my shelves waiting for me to find the time to read it. The discussion centred around Grayling's portrayal of the arguments for God, with Williams and the host highlighting what they saw as the problems with Grayling's thinking on the arguments.
It might be worth getting into the discussion around the moral argument another time, but for now I want to focus on an analogy that Peter Williams gave for the fine-tuning argument. The analogy goes something like this: lets suppose I've taken your bank card and I've tried to withdraw money from an ATM, but I did not know your pin. Yet despite this limitation, I was able to guess the pin and withdraw the money. It seems really improbable that I was able to do so, and you'd be sceptical that I was able to do so without that knowledge. For a four-digit pin, that's ~1/10000 chance. Yet when we look at all the ways the universe could exist, the fraction that allows for something even remotely like life is near infinitesimal. It follows that just like we see someone guessing as an unlikely explanation, that to say the universe happened by chance for our benefit is an unlikely explanation.
The next step, as far as theism is concerned, is to use design as a way of providing an explanation. This analogy is contrasted with Grayling's own analogy of trying to think about all the unlikely circumstances that would lead to his existence - that things had to happen for his parents to meet and for them to reproduce when they did, and so on back through the ages, whereby the chain of events is incredibly improbable, yet that fact doesn't require any other explanation.
While I do have suspicions about Grayling's argument in the way it was presented, I'll reserve judgement until I've read his book. Prima facie, Williams looks to have a point about the inadequacy of such a statement, but I think that Williams analogy is a step in the wrong direction. The reason has nothing to do with how to calculate the probabilities of life and how universes come about - as I lack the sufficient knowledge of physics to even begin to ponder the meaning of the question - but that in what we do know about the history of life in this universe, Williams' analogy seems utterly nonsensical.
Contingency already plays a huge role in the world as it is now. If the non-avian dinosaurs weren't wiped out by catastrophic events 65 million years ago, then there wouldn't have been the rise of mammals, the evolution of hominids, and even analogies like the ATM machine one. Yet the extreme unlikelihood of those events for our existence don't suggest that we should think of the plate tectonics and killer asteroids as being guided by a purposive designer for our benefit.
Even if the universe could be argued to be improbable on its own, it seems apparent that we cannot tell the story of our own existence without invoking chance and contingency in a sufficient and explanatory way. For the analogy, it's worth reflecting on just how lucky we are to be here with no other explanation beyond the happenings of how life evolved on this planet given the circumstances of the planet. The pin analogy makes it seem like the idea of fine-tuning means that we're the product of this fine-tuning. Yet there's no reasonable reason to think this is so.