Divine Motivation and Bayesian Natural Theology
Bayesian arguments play an important role in debates about the existence of God in natural theology. A successful Bayesian argument for theism should show that, relative to competing hypotheses such as naturalism, theism does not have a very low prior probability and is better able to explain certain general features of the world. Proponents of such arguments for theism, such as Richard Swinburne, have argued that there is no tension between the prior probability and the explanatory power of theism because certain of God’s fundamental attributes – omnipotence, omniscience, and perfect freedom – jointly entail the explanatorily powerful attribute of perfect goodness. If this is correct, then ascribing perfect goodness to God does not make the theistic hypothesis any more complex than does the ascription to God of those fundamental attributes. However, this argument presupposes the truth of a certain package of controversial metaethical claims. I argue that we have good reasons to reject this package of claims.
After introducing these key concepts and responding to an objection in the first chapter, I map out models of divine motivation – pure rationalist, modified rationalist, and Humean models – in the second and third chapters. Pure rationalism holds that God is perfectly rational and perfectly free from non-rational causal influences, including non-rational desires. On this model, God is motivated by objective reasons alone. Chapter two explicates and assesses the pure rationalist accounts of Swinburne and Mark Murphy while chapter three develops the modified rationalist and Humean alternatives and argues that these models better handle problems of divine creation and freedom than do pure rationalist models. According to modified rationalism, God is motivated by the recognition of objective reasons, but is also motivated by brute preferences or desires. Humean models hold that all of God’s motivation derives from brute preferences or desires. The fourth chapter focuses on moral motivation, primarily the Humean theory of motivation. I develop a more permissive, and so more easily defensible, version of Humeanism. The fifth and final chapter brings together my defense of Humeanism and discussion of divine motivation to argue that there is strong reason to accept the Humean model of divine motivation. However, accepting this model comes with a cost to the Bayesian natural theological argument for God’s existence because it is incompatible with the claim that God’s being omniscient and perfectly free jointly entail God’s being perfectly good.
- Doctor of Philosophy
- West Lafayette