At the end of his iconic novel Candide, Voltaire says "We must cultivate our garden". This has always been one of my favorite quotes from the Enlightenment because it crystalizes the modern notion that human society is a human endeavor which like a garden can be improved through rational, benevolent human intervention. The notion that the status quo is not determined by divine providence but by socio-economic factors that we have control over is one of the things that separates us from medieval society and is the foundation of our participatory democratic political system.

This rather idealistic notion has been tempered by Darwinism and the secularist notion that human societies exist in a state of nature where individuals compete for resources in order to survive and pass their genetic characteristics onward. One of the original sources of controversy for Darwin's theories was not their religious implications but the fact that they challenged the assumed notion that Nature was a benevolent force. Thus Social Darwinism has replaced divine providence as an explanation and justification for social inequality.

However this isn't the whole story. Our mastery over the animal kingdom has nothing to do with our physical characteristics. We are frail creatures compared to the other dominant predators we once competed with in a state of nature, and even compared to much of our prey. It is our advanced mental capacity and our ability to work together that sets us apart from other animals.

This editorial from the New York Times cites recent research that suggests that cooperation, sharing, and altruism are a natural part of our mental makeup. Like everything about human civilization this is a two-sided coin, because while it explains our sense of justice it also explains our tribal nature by which we divide ourselves into cooperative groups that compete - often violently - with other human groups.