Consider the hypothesis that contingent reality popped into existence uncaused.
Now, either popping into existence uncaused is astronomically unlikely or not astronomically unlikely.
If it is astronomically unlikely, then we have a very strong Bayesian argument for theism. For then P(contingent reality | no God) is astronomically small while P(contingent reality | God) is at least moderately high.
If uncaused popping into existence is not astronomically unlikely, then there are two main options. The first option is that there is no meaningful probability of such an event. In that case, there is no meaningful probability of Maxwell’s Demon popping into existence for no cause at all in one’s lab. But if Maxwell’s Demon were to pop into existence in one’s lab, then one wouldn’t expect to get the predicted observations. Thus, if there is no meaningful probability of things popping into existence for no cause at all, then there is no meaningful probability of our scientific predictions, and science falls apart. That’s not acceptable.
The other option is that there is a probability, and it’s not astronomically small. But then at every moment of time, it is not astronomically unlikely that an object would causelessly pop into existence. Since there are astronomically many moments of time during a second (perhaps infinitely many, but at least equal to the number of Planck times in a second, i.e., of the order of 1043), it seems we should expect to see lots of objects pop into existence causelessly. And we don’t observe that.
There is lots of technical detail to fix in this argument.
