When people say that "we're all basically selfish" they are equivocating, or confusing, different meanings of the word "selfish". Of course we are all concerned with our own survival, but man is a very weak animal on his/her own. We all depend on other people. So there is a clear social dimension to all of us. We would not exist as individuals, as persons, without a group or a society. And social life requires that we look after the interests of other people too and not just ourselves. So we're basically unselfish too. If you treated other people like ~ all the time, they would treat you badly too, and eventually you would die in total isolation.