It's not a well-defined enough hypothesis to assign a number to: but the the main thing is that it's going to be very low. In particular, it is going to be lower than a reasonable prior for a universe coming into existence without a creator. The reason existence seems like evidence of a creator, to us, is that we're used to attributing functioning complexity to an agent-like designer. This is the famous Watchmaker analogy that I am sure you are familiar with. But everything we know about agents designing things tells us that the agents doing the designing ... (read more)