Whatever its concrete scientific benefits turn out to be, intelligent design theory has already succeeded in reasserting science's rooted-ness in theology's quest for a normatively unified sense of ourselves as enquirers and the reality into which we enquire. However, this quest for normative unity poses its own deep problems, ones that constitute a field that has periodically surfaced in this book: theodicy. It is now normally treated as a boutique topic in philosophical theology that is concerned with how a perfect God could have made such a miserable world. Put still more provocatively: how can a good God allow evil to exist? Nevertheless, theodicy was the original science of intelligent design, a comprehensive master discipline that hails from a time – the late seventeenth century – before theology, philosophy and science were neatly compartmentalized into discrete academic fields. The fundamental question posed back then was how could the divine creator, who is described in the Bible as omniscient, omnipotent and omnibenevolent, produce a world that is imperfect in so many respects. In what sense, then, could all this imperfection add up to ours being, as Leibniz, author of the first book called “theodicy”, notoriously wrote, “the best of all possible worlds”?

Theodicy remains relevant today for at least two reasons. First, it concedes at the outset that nature contains palpable imperfections, ranging from unexplained natural catastrophes and monstrous births to senseless deaths and more everyday examples of suboptimal design in organisms.