God's existence is a testable hypothesis about the universe, not a separate category of truth

Dawkins's central methodological move is refusing to grant religious claims a special exemption from ordinary standards of evidence. If a god intervenes in the physical world — answering prayers, creating species, inspiring texts — then that god's existence is, in principle, a claim about reality that should leave traces, and traces are checkable.

He rejects the idea that faith and science operate in separate, non-overlapping domains, arguing instead that most religious traditions do make specific, testable claims about how the universe works and how it came to be, not merely claims about meaning or morality. Once you grant that a god causally affects the world, you've made an empirical wager, not a purely spiritual one.

This reframing is the foundation for everything that follows in the book: because if God's existence is empirical, it can be assigned a probability, weighed against alternative explanations, and updated as evidence accumulates — exactly like any other scientific question. Treating God's existence as a factual claim about reality, rather than an unquestionable premise, is what allows it to be evaluated with evidence at all.