ABSTRACT
A posteriori arguments for the existence of God can be arranged in an order by the generality of their premises. The cosmological argument argues from the fact that there is a universe at all; one form of argument from design argues from the operation of laws of nature (i.e. that all the constituents of the Universe behave in a law-like way), and another form of argument from design argues from the laws and boundary conditions of the Universe being such as to lead to the evolution of humans, claiming that rather special laws and boundary conditions are required if the Universe is to be human-lifeevolving. The normal way in which this latter is expressed is to claim that the constants and variables of those laws and boundary conditions have to lie within very narrow limits in order to be human-life-evolving. This argument is therefore called the argument from fine-tuning. There are, then, many other arguments that begin from narrower premises. The arguments are, I believe, cumulative. That is, the existence of a universe raises the probability of the existence of God above its intrinsic probability, its probability on zero contingent evidence. The operation of laws of nature raises it a bit more, and so on. Counter-evidence, e.g. from the existence of evil, might lower that probability. I have argued elsewhere that the total evidence (i.e. everything we—theists and atheists—agree that we know about the Universe) makes the existence of God more probable than not. 2 My concern in this chapter is solely with the force of the argument from fine-tuning: how much more probable the human-life-producing character of the laws and boundary conditions makes it that there is a God than does the fact that there is a law-goveraed universe.
