I’ve often wondered about ethical egoism (though I didn’t really have that term), the philosophy made popular by Ayn Rand that pretty much argues that you ought to act in your own self-interests; mainly, my interest has been in its refutation. James Rachels, in The Elements of Moral Philosophy, makes a strong argument that ethical egoism is “unacceptably arbitrary.” He makes an analogy with racism (note: an analogy; he is not calling ethical egoism racist): since there are no general differences among races, “racism is an arbitrary doctrine, in that it advocates treating people differently even though there are no differences between them to justify it” (89).
Likewise, ethical egoism is unacceptably arbitrary because there is no general difference between oneself and others: I should not favor myself because I am not more special than anyone else. Rachels concludes his chapter on the subject:
We should care about the interests of other people for the same reasons we care about our own interests; for their needs and desires are comparable to our own. Consider, one last time, the starving children we could feed by giving up some of our luxuries. Why should we care about them? We care about ourselves, of course — if we were starving, we would go to almost any lengths to get food. but what is the difference between us and them? Does hunger affect them any less? Are they somehow less deserving than we? If we can find no relevant difference between us and them, then we must admit that if our needs should be met, so should theirs. It is this realization, that we are on a par with one another, that is the deepest reason why our morality must include some recognition of the needs of others, and why, then, Ethical Egoism fails as a moral theory. (89-90)
Rachels, James. The Elements of Moral Philosophy. 4th ed. Boston: McGraw Hill, 2003.