Although Adam Smith did not think that utility is the main principle in moral judgment, it is a key concept in understanding the whole picture of his moral philosophy. This paper shows that his concept of utility has two levels: the level of man and the level of God. Smith thought that human nature has utility at the level of God, and that the existence of this God can be proved through the utilitarian argument from design. Smith rightly recognized that this view of “final cause”makes a contribution to the explanation of “efficient cause” in moral philosophy.