At the heart of every inquiry into what is ethical is the question of whether human beings have free will -- that is, exactly how much control do we have over our own actions? This issue also figures centrally in the historic debate over spirituality or science. Many modern thinkers, however, suggest that there's a third way of getting at the truth of human nature.
Michael Gazzaniga argues that while "free will" is not something intrinsic to the biology of human beings, people are participants in social networks and have a social obligation to act in accordance. Daniel Dennett believes that "the business of asking somebody why do, why did you do that?" arose in humans through the process of evolution. So while there is no universal religious truth behind our moral underpinnings, the fact that they are there elevates us in some way above the animals. Antonio Damasio envisions the self as "the organizer of life." There's no "ghost in the machine," says Steven Pinker -- behavior is a product of physical processes in the brain -- but the overwhelming complexity of the brain means that human choices are not predictable or predetermined.