Who designed the designer? A God capable of fine-tuning a universe is far more complex and improbable than the universe, so design explains the improbable by the more improbable.

This is Dawkins’s central argument and it has to be answered. The theistic reply, from Swinburne, Plantinga, and others, is that God is not a complex physical arrangement of parts and so is not improbable in the way a physical structure is; simplicity in explanation is about the number of independent postulates, and a single necessary mind is arguably simpler than a multiverse of unobservable universes. Dawkins’s critics also note that explanations do not need to explain their explainers: one can infer a designer from a watch without knowing the watchmaker’s origin. The debate is philosophical, and both sides are worth reading.