What makes us human? That is an ongoing debate, though some people cite "language," "technology," and "culture." They are wrong, of course, because nonhuman animals have all three, albeit in very different forms. A better description of human uniqueness might be "civilization." Not just the formation of societies - ants do that far better - but cities and civilian rules of conduct. We have developed highly sophisticated rules of conduct that are, whether their inventors realized it or not, ways of balancing the innate need to survive ("selfishness") with the needs of the group (altruism or cooperation). This balance would have existed before we moved into cities (the origin of the term), but the intense crowding (relative to pastoral or hunting-and-gathering times) made externalized, recorded rules an absolute necessity to avoid anarchy. Other social animals have rules of conduct - otherwise chimpanzees and bonobos, for example, would not appease each other after a fight - but they are not Socratic, Confucian or Jeffersonian. Homo sapiens grapples with complex matters of psychology and sociology and comes up with ways of minimizing suffering and maximizing overall peace and prosperity. Since there is still plenty of suffering in the world, it would seem the efforts by the Great Minds over the millennia have been in vain. But try to imagine for a moment where our species would be now if not for their devotion to explaining human nature. We may have destroyed ourselves centuries ago.
One of the greatest personal dilemmas is to think beyond our own needs. A relatively easy one is concrete: e.g., giving a friend the last cookie. Many humans limit their "generosity" to the concrete - if only in the spirit of enlightened self-interest (e.g., reciprocal altruism, where the favor is expected to be returned one day). Social animals are incapable of any other kind.
Abstract selflessness is the truest test of character, of being civilized. Not many people are capable of denying or even hurting themselves in order to honor an ideal. Ideals don't say thank you. They don't return favors. Many organized religions recognize this psychological dilemma, and promise rewards in the hereafter. (They are still abstract, but at least your selflessness seems to involve cause and effect.) Community respect can also serve as reward for such things as patriotism and volunteerism. (Of course, the most generous of givers are anonymous.)
I heard Jonathan Safran Foer on the radio this morning talking about his book Eating Animals. (See earlier post below.) He repeated something from his book, an excerpt of which I read a few weeks ago. Hearing it, I was moved again. His beloved grandmother narrowly survived death by starvation in WWII Russia. One day, a local man offered her a piece of meat. She refused - because it was pork, and her principles (=Mosaic laws) forbid its consumption. As affecting as that image may be, that was not the moving part. It was how she responded to her grandson's flabbergasted question: you wouldn't eat it, even to save your life? She said, "If nothing matters, there's nothing to save."
By thinking beyond - sometimes way, way beyond - the skin of the Self, we create meaning. And that unites us a human beings, and makes life worth living.
I will think about that the next time I nearly buy something my research has taught me hurts another person or creature. In moments of weakness, I find myself saying "I am the only one doing this, so why bother?" That's why.