The “Intrinsic Probability” of Theism

by Ben Mines

Before coming to the evidence for the existence of God, a preliminary question needs to be asked: How plausible is it, a priori, that God exists?

Consider the case of John and Jane. John assumes that the existence of God is profoundly unlikely and therefore views theistic proofs with deep suspicion and finds them unpersuasive. Jane, on the other hand, assumes that the existence and nonexistence of God are about equiprobable and therefore views those same proofs with an open mind and finds them persuasive.

The point is that our presuppositions about the “intrinsic probability” of theism (where the “intrinsic probability” of a hypothesis is a measure of its simplicity prior to the evidence) are crucial to the outcome of any discussion of evidence for the existence of God and so need to be taken into account. [1]

It is at first tempting to think that John is correct. The existence of God seems about as improbable as anything can be. God, if he exists, is unlimited: infinite in power, knowledge and love. The principle of parsimony, which recommends the simpler of any two competing explanations, would seem to recommend an atheistic explanation in every possible case: Whenever there are two possible explanations for the evidence, one which appeals to the existence of God and one which does not, the explanation which does not appeal to the existence of God is simpler and therefore has greater intrinsic probability. Prejudice against theistic claims is, it seems, justified…


The “Intrinsic Probability” of Theism | Thinking Matters