There is a difference betwene selfish and self-intersted. I am active in pursuit of my own self-interest, but always with the larger pcture in mind, that the interest of every otehr person must be considered as well and that my self-interest must be tempered by respect froyour legitimate self-interest.
Selfishness is something else again: the pursuit of our own interests, no matter what.
Darwin's Dilemma: society militates against his theory.