David Brooks has written a column for the New York Times in which he discusses the idea that morality is a product of our evolutionary past. According to this view, our ancestors developed a sense of what successfully facilitated social cooperation, and that therein lies the basis of an innate moral sense that all of us have (and which even small infants show some expression of). Interestingly enough, Brooks makes a connection in his article between morality and justice; he quotes a researcher who says that "people have a rudimentary sense of justice from a very early age."
He also discusses the relationship between morality and empathy:
People who behave morally don’t generally do it because they have greater knowledge; they do it because they have a greater sensitivity to other people’s points of view. Hauser reported on research showing that bullies are surprisingly sophisticated at reading other people’s intentions, but they’re not good at anticipating and feeling other people’s pain.The very existence of bullies points to the fact that not everyone has an equally developed sense of morality--bullies seem to express less moral sense than compassionate people, at least when they bully others--which ultimately implies that not everyone has an equally developed sense of empathy. Even if there is an innate moral sense within us as humans, it is still something that needs to be cultivated to be fully manifest. And this struggle to cultivate our morality has been played out in human history. Oppressive human social structures and ideologies--the list is long, but could include such things as slavery, sexism, racism, oligarchy, torture, economic exploitation--can all be seen as examples of an institutionalized lack of empathy. It has been a historical struggle to cultivate greater empathy at a societal level in order that people might understand that, for example, sexism is a bad thing, and further that society should reflect this understanding at an institutional level. Achieving this understanding has meant appealing to people's innate moral sense, their sense of justice, to inspire them to alter societal structures to make them more just.
When we stand up for society's victims--the poor, the oppressed, the immigrant, the religious minority, the excluded--we are expanding upon that innate moral sense and that innate sense of justice. But that innate sense will be stunted unless it is nourished. The seeds of justice may lie within us, but we have to cultivate them to make them grow.