Frans de Waal’s essay explores morality and religion among humans by looking at empathetic behaviors found in primates and other animals:
According to most philosophers, we reason ourselves towards a moral position. Even if we do not invoke God, it is still a top-down process of us formulating the principles and then imposing those on human conduct. But would it be realistic to ask people to be considerate of others if we had not already a natural inclination to be so? ...
Instead, I am a firm believer in the Humean position that reason is the slave of the passions. We started out with moral sentiments and intuitions, which is also where we find the greatest continuity with other primates. Rather than having developed morality from scratch, we received a huge helping hand from our background as social animals.
Jerry Coyne scoffs at de Waal's final point that an "atheist morality would wind up looking religious":
I look forward to worshipping St. Hitchens at Our Lady of Perpetual Dickishness, and to receiving infallible proclamations from the chair of His Holiness Pope Cephalopod. The idea that secular morality would look like religion is ridiculous, and is completely dispelled by the example of modern Europe.
But Hume was onto something. And he also noted something that other moderns have forgotten, that acts of kindness and generosity actually make us happy. That natural correlation between virtue and happiness has been occluded by the Augustinian notion that being good means repression and self-denial. Often giving to others is the surest way to sanity, well-being and happiness. To give is to receive. And this seems not to be against the grain of our nature, but with it.