This paper is a critique of Richard Dawkins’ “argument from improbability” against the existence of God. This argument, which forms the core of Dawkins’ book The God Delusion, provides an interesting example of the use of scientific ideas in arguments about religion. Here I raise three objections: (1) The argument is inapplicable to philosophical conceptions of God that reduce most of God’s complexity to that of the physical universe. (2) The argument depends on a way of estimating probabilities that fails (...) for the probability of an entity that creates natural laws. (3) The argument supposes that complexity arises from past physical causes; however, some forms of complexity known to mathematics and logic do not arise in this way. After stating these three criticisms, I show that some of these same considerations undermine Dawkins’ critique of agnosticism. I close the paper with some remarks on Dawkins’ conception of God. (shrink)