In this article on the biological underpinnings of empathy, researcher Brian P. Lewis makes this fascinating remark:
Brian P. Lewis of the University of California, Los Angeles, has argued that empathy can exist quite well without altruism. This is because the self isn’t necessarily located in a single individual. Therefore, we can empathize with and help someone else simply because we see ourselves in them.
In modem theories of the self, as well as in current evolutionary thought, important features of the self can be located outside of the person and inside others. The possibility exists, then, that empathy associated helping is not selfless but is rooted in the (usually implicit) desire to help that part of the self that is located in the other.