Assessing the case for theism › What would count as a good reason to believe?

Imagine two people looking at the same night sky. One sees evidence of a creator in its order. The other sees a physical universe whose regularities still need explaining. Neither observation settles their disagreement. They need to ask what each explanation adds, which assumptions it requires, and what would count against it.

That is the task J. L. Mackie undertakes in The Miracle of Theism. His conclusion is atheist: he judges the overall case against the existence of God substantially stronger than the case for it. Yet the route to that conclusion matters as much as the verdict. A failed proof need not be worthless evidence, several modest arguments might reinforce one another, and a possible explanation need not be a probable one. Losing these distinctions makes both belief and unbelief too easy.

The title has a Humean irony. In his introduction, Mackie distinguishes a supernatural intervention from the older sense of a miracle as something surprising. His target is the continuing conviction of reasonable believers, despite what he regards as inadequate support. He also thinks religious belief can have a natural history. Its persistence therefore need not itself involve supernatural intervention. The title expresses his judgment about the arguments, not an extra proof against God. Mackie, Introduction, pp. 11–12.