This chapter explores the implications of the new status of belief by reconsidering traditional arguments for the existence of God. If disbelief in the supernatural was not a live option before the appearance of modern secularity, what was the point of articulating proofs of God’s existence? This chapter shows that the so-called classical proofs performed a very different function to the one that they were later to assume, being more akin to spiritual exercises than logical arguments constructed from neutral premises. Crucially, one of the central ‘proofs’—that based on universal consensus—involved an appeal to the ubiquity and universality of religious belief. The demise of this ‘argument’ in the early modern period signalled a major change in how belief in the supernatural came to be understood, indicating that the burden of proof was shifting from unbelievers to believers. This was accompanied by a new conception of natural theology, understood as an enterprise that could provide support for religious belief on rational grounds alone. The changing status of natural theology and proofs for God’s existence correlated directly with the appearance of a new notion of belief and the requirements for its justification.

The authors run through the major arguments for the existence of God: Anselm’s ontological argument (and also Descartes’s version), arguing that the very notion of God a priori proves hs existence; Aquinas’s cosmological (or causal) argument, that God is needed to stop an infinite regression of causes from the present to the past; and the teleological argument or the argument from design, that the design-like natural objects of this world demand a designer. Then they raise the standard objections: Gaunilo’s criticism that the ontological argument proves the existence of perfect islands, which is ridiculous, and Kant’s objection that you cannot infer matters of fact by a priori reasoning; Dawkins’s criticism that the cosmological argument raises the unanswered question of what causes God; and Hume’s criticism of the design argument, and Darwin’s subsequent demonstration that natural selection can explain final causes naturalistically, and so there is no need to invoke a Designer God.