Richard Dawkins' atheism has provoked a series of intelligent books about religion, from Marilynne Robinson's Absence of Mind and K aren Armstrong's The Case for God to this anthropological and philosophical enquiry by Robert Wright, an agnostic.
Wright wants to explain "how the conception of God has changed in response to events on Earth". He wants to show the shifting sands beneath stories apparently set in stone. And so he begins with the earliest human societies, the hunter-gatherers, to show religion without a moral element, before moving on to chieftain societies and their reliance on the supernatural.
What can they tell us about our attitude to God today? Wright traces the passage from polytheistic cultures to the monotheistic one that the Old Testament glories, as well as the older parts of the Bible that show a destructive, warrior God rather than the creative one we're perhaps more used to. It's taken as a given that human beings need something to believe in, some sense of a higher power, but what is interesting is that Wright harnesses that need to moral progress.
He argues that, in spite of the wars still raging around the planet, humans have, in general, improved morally, and that the main reason has to be belief in a higher purpose. Evolution, in other words, has a moral contingency: we are programmed to evolve into better human beings. Why?
Wright's style is pugnacious and colloquial but that doesn't mean it lacks subtlety or slams down opposition. But his take on the "invention of Christianity" is provocative because he looks at the Bible as a historian would, to argue that the scriptures "recast the past in a way that obscured the actual evolution of doctrine". Religion, though, should be leading towards the light, not taking us away from it.