Note: This is a rambling argument against ethical egoism; I'm saying that it doesn't make sense to reject altruism, especially using evolution as an argument, and in fact, evolution can be used to explain how altruism can be evolved. I'm not talking about possible solutions or theories of socio-economic organization. Obviously, philosophy informs those ideologies and the rejection of ethical egoism has implications in that regard. But that's another topic.
I can't believe that ethical egoism is even considered to be a valid moral-framework. It essentially legitimizes being a selfish asshole who has no regard for the feelings of others; a narcissistic psychopath would be the supreme ethical-egoist. This is absolute nonsense. It is argued that altruism doesn't "make sense" because looking out for another person when it's not even in your interest doesn't jive with "natural selection" (something right libertarians are in love with). That's still generally true; evolution is ruthless competition -- the amoral laws of nature or the "law of the jungle". But there is also emergent complexity.
When you start dealing with agents that not just aware of themselves, but also other agents like them, then they must necessarily be aware of the consequences of their actions, on such agents. This was a foregone conclusion, I think, once sexual reproduction evolved. At some point, a creature would evolve that needs to be aware of opposite sex, and needs to be able to maximize its chances of reproducing with that opposite sex. That requires an internal cognitive framework (or at least embedding so that we don't have to quibble about sentience) that can represent an "other". Naturally, this will give rise to cooperation, because even by chance two agents can discover that their chances of success at gathering resources (food; i.e., energy) is maximized if they work together. From here it's not too difficult to see how packs, herds, and flocks evolved. Once the brain already has a sense of the opposite sex, it's not hard to extend that to other members -- I would argue that that would have necessarily evolved at the same time as awareness of the opposite sex because agents usually have to compete with members of their own sex for access to the opposite. Hence again, even by chance, it is possible for agents to discover that by working collectively, their chances for success are maximized. This is especially observed in pack animals from wolves, and in primates, especially in us.
If early humans only looked out for themselves, we would have gone extinct. This is because by himself or herself, a single human-being is not a formidable predator; we don't have big, sharp, teeth or claws. We aren't especially hardy either; we don't have fur and we are comparatively frail when compared to other predators that occupy the same niche. This is true for many primates as well. But what maximized the chance of not just group, but individual success and survival, is working together as a group. To do that necessarily requires altruism, since the agent must be able to balance individual needs against the overall well-being of the group. For example, when a group is attacked, healthier individuals will protect the injured, old, and young -- this puts them at more risk, but they do it regardless because group survival is only guaranteed by the protection of those who cannot protect themselves. With humans this reaches a different stage. No longer guided by the blind evolution, our sentience lets us explore the solution space of social-organization even further. Our sense of self , our metacognition, lets us question norms and wonder about other social arrangements.
But that one can explore this solution space means that one will encounter both bad and good solutions. Ethical egoism is bad solution. That it has been conceived of, doesn't give it any validity. Individuals purely acting in their own self-interest may lead to a functional society, but it is not one that is necessarily equal (it is highly improbable+ that it would be); where the rights of a percentage are not being continually oppressed -- disregard of the rights or feelings of others necessarily leads to that. As human beings, our chances of survival are maximized by having concern about our fellow humans. In these times, we're talking about the survival of human civilization itself.
Ethical egoism as a moral framework should be rejected.
+I have this intuition about a game-theoretic agent-based framework that could perhaps provide evidence for this. I would need to use an inequality measure of some sort and then run thousands of simulations to get a distribution of values for the coefficient, and the parameters (types of cost-functions, basically) that produce those values. I haven't fully thought it through because I have other stuff to work on, but it's an experiment I'd like to try one day.
I’m not sure you’re talking about actual altruism [btw just so you know I’m altruistic, also libertarian and definitely not what they are calling “left libertarian” nowadays, dunno about right]. Something along the lines of “herd instinct” isn’t necessarily the same thing as a cognitive decision to help someone even if you know it will hurt you in some way. Just like we don’t know why we’re attracted to someone, we “just are”, we can have the same instinctual “we have to protect that weak element of our herd” where we are actually not being deliberately altruistic but just following our genetic/epigenetic orders without really knowing why.
I’m not really arguing against your general line of thought but kind of asking what it is you’re really arguing about. If “ethical egoism” is basically a Randian idea, then I’m not sure that what you’re arguing here is arguing against their version (not a Randian personally) of altruism.
Also, you have to consider that Rand came from a place where “altruism” generally meant “what the totalitarian government forces you to do in the name of helping the collective”, so I don’t really know that what Rand was arguing against is really, truly, voluntary altruism.
I haven’t read Rand extensively, though, but I know that what the communists called altruism was a big theme and rallying cry. Rand probably (I’m guessing here) saw guilt-enforced altruism (via religion, for example) as the same thing in a different cloak.
The flavor of libertarian I hang out with (Rothbardians, more or less) are a very altruistic bunch. What we object to is what you might call “forced ‘altruism'” with the sarcastic quotes around “altruism” highly emphasized–there’s nothing generous about giving up your money at the point of a government gun to subsidize unemployment and destroy work ethic, we might point out.
Sorry, this is at least as rambling as the original. I enjoyed reading it. “the evolution of altruism” has some google results you might be interested in.