I was googling around trying to remind myself which philosopher had a similar story told about him. I thought it was Nietzsche, but it was apparently Hobbes, if Etzioni had it correct (viz). Hobbes famously denied the possibility of altruism, and when caught giving alms to a beggar, claimed he was doing it for his own benefit, because it hurt him to see a man so hungry.
Hobbes’ refutation is semantics: he has effectively defined altruism to mean an act by which the giver receives no benefit at all — not even the warm fuzzies of thinking oneself a better person. But that definition pretty much eliminates the possibility. If altruism is an intentional act (e.g., one can’t be altruistic accidentally), then there must be some sense, however abstract, in which one wants it, thus providing some utility to oneself.
A more useful definition has evolved for altruism is an act that benefits and has a cost to the giver. As long as the giver and receiver are related in some way, that’s pretty easy, since kin selection (and, perhaps, group selection) theories tell us that a sacrifice for someone that carries genes very similar to one’s own can still be self-centered from an evolutionary point of view (or is a member of one’s own cultural group, in group selection).
It gets tougher when giver and receiver are strictly unrelated, but even then there is still evidence, and some theory about how it came about.
When I donate blood (and I do to the extent of twelve gallons over the past three decades), my act comes at a cost to me — small, of course, unless something goes wrong. The benefit accrues in way I have no control over — the recipient could be someone I despise and would prefer to see dead, and I will never know. Since almost no one of my acquaintance knows when I give blood, this can’t be said to be enhancing my reproductive chances, so why would I do such a thing?
The current theory is that it is a cultural expansion of evolved tendencies. As a species we acquired kin selection altruism when we were a the social level of our ape relatives. Once cultural continuity help with our survival (e.g., when the number of tools and techniques our clan depended on surpassed what one family could pass on to its children), then the need for survival of non-kin pushed altruism (and related cognates such as patriotism) beyond kin circles, for to tribes, then to entire societies. Since those latter concepts are fairly flexible, it doesn’t take too much for a cosmopolitan to extend altruism to strangers.
But, yes, Hobbes was right. We do it, in the end, because it makes us feel good to help other people.