Moral sentiments came first; moral principles second.”

According to Piaget and Tomasello, moral understaing begins to emerge at around the same time as the child comes to understand others as mental agents.
 It derives not from the rules adults impose on behavior, but from empathizing with other persons as mental agents and being able to see and feel things from their point of view.
 

Within Western moral philosophy there is a long tradition going back to Immanuel Kant that privileges reason over feeling. To act out of duties legislated by reason is thought to have greater moral worth than acting on the basis of feeling or sentiment. Yet as Frans de Waal observes, echoing David Hume and Adam Smith: “Aid to others in need would never be internalized as a duty without the fellow-feeling that drives people to take an interest in one another. Moral sentiments came first; moral principles second.”

Empathy is the basic cognitive and emotional capacity underlying all the moral sentiments and emotions one can have for another. The point here is not that empathy exhausts moral experience, for clearly it does not, but that empathy provides the source of that kind of experience and the entry point into it. Without empathy, concern and respect for others as persons in the moral sense—as ends-in-themselves—would be impossible.