Abstract

Natural theologians often claim that God exists necessarily, so that his (alleged) existence does not need an explanation. Various notions of necessity are analysed in order to determine in which sense God’s existence can be called ‘necessary’. Richard Swinburne’s claim that God exists necessarily in the _ontological_ sense boils down to admitting that God’s existence, if he exists, is radically contingent. Furthermore, Swinburne’s use of Kripke’s notion of _de re_ necessity in order to explain in which sense God’s defining properties are ne cessary properties is unconvincing for various reasons. Finally, Swinburne’s introduction of analogy into his use of the term ‘person’ for God in order to resolve a contradiction concerning God’s necessary properties implies that no proof of the coherence of theism is possible. In particular, there is no conceivable _indirect_ proof of the coherence of theism by adducing evidence to the effect that theism is probably true. It follows on the usual criteria for theory choice that theism is not eligible as an existential hypothesis open to empirical confirmation.