The Intrinsic Probability of Grand Explanatory Theories

This paper articulates a way to ground a relatively high prior probability for grand explanatory theories apart from an appeal to simplicity. I explore the possibility of enumerating the space of plausible grand theories of the universe by using the explanatory properties of possible views to limit the number of plausible theories. I motivate this alternative grounding by showing that Swinburne’s appeal to simplicity is problematic along several dimensions. I then argue that there are three plausible grand views—theism, atheism, and axiarchism–which satisfy explanatory requirements for plausibility. Other possible views lack the explanatory virtue of these three theories. Consequently, this explanatory grounding provides a way of securing a non-trivial prior probability for theism, atheism, and axiarchism. An important upshot of my approach is that a modest amount of empirical evidence can bear significantly on the posterior probability of grand theories of the universe. My aim in this paper is to articulate an alternative grounding to a relatively high prior probability for grand explanatory theories of the universe. This is important for empirical arguments for such theories. For instance, one argument for theism ∗My thanks to Scott Davidson, Chris Dodsworth, Michael Ferry, Nicholas Jones, Daniel Massey, Kevin McCain, Thomas Metcalf, Calum Miller, Mark Murphy, Richard Swinburne, and Chase Wrenn for helpful comments on a previous draft. An earlier draft of this paper benefited from useful discussion at The Society for Philosophy of Religion. I am grateful to two anonymous reviewers of this journal for in-depth comments. Any errors that remain may be credited to the entropy of the universe, to Karen, or to the author’s failure to heed the sensible advice of superb colleagues.