Abstract
What, if anything, are we morally required to do on behalf of others besides respecting their rights? And why is such regard for others a reasonable moral requirement? These two questions have long been major concerns of ethical theory, but the answers that philosophers give tend to vary with their beliefs about human nature. More specifically, their answers typically depend on the position they take on a third-question: To what extent, if any, is it possible for us to act altruistically?