Sam McNerney in Why We Reason:
It is often argued that religion makes individuals and the world more just and moral, that it builds character and provides a foundation from which we understand right from wrong, good from evil; if it wasn’t for religion, apologists say, then the world would fall into a Hobbesian state of nature where violence prevails and moral codes fail. To reinforce this contention, they point out that Stalin, Hitler and Mao were atheists to force an illogical causal connection between what they did and what they believed.
One way to answer the question of if religion makes people and the world more moral and better off is to look at the history books. For that, I draw upon Steven Pinker’s latest, The Better Angels of Our Nature, an 800 page giant that examines the decline of violence from prehistoric hunter-gatherer societies to the present. Pinker opens his book with the following: “Believe it or not – and I know that most people do not – violence has declined over long stretches of time, and today we may be living in the most peaceable era in our species’ existence. The decline, to be sure, has not been smooth; it has not brought violence down to zero; and it is not guaranteed to continue. But it is an unmistakable development, visible on scales from millennia to years, from the waging of wars to the spanking of children.” Whether you’re familiar with Better Angels or not, it’s worth reviewing its arguments to show why violence declined. Let’s run through three sections of Pinker’s book – The Pacification Process, The Civilizing Process, and The Humanitarian Revolution – to see how violence declined. Doing so will allow us to judge if history has anything to say about religion being a credible source of moral good at the individual and global level.