Imagine that you are an astronomer on a world with one moon. It is always night on your world, and the moon is the only body in the sky.
Nature is like a stack of books, sessile, until moved.
In my ongoing debate with biologist Jerry Coyne, frequent reference is made to Aquinas’ Five Ways, particularly to his Prime Mover argument.
Because the challenge is perennial, and because we’re not all philosophers, it’s good to come back to it from time to time.