"A cosmological argument is an argument to the existence of God from the existence of some finite object or, more specifically, a complex physical universe. There have been many versions of the cosmological argument given over the past two-and-a-half millennia; the most quoted are the second and third of Aquinas’s five ways to show the existence of God. However, Aquinas’s ‘five ways’, or rather the first four of his five ways, seem to me to be one of his least successful pieces of philosophy."