There is a word which is the bane of every dictator, every iron fist, every dark lord, and every god. That word is self. All words pertaining to the self are also considered evil by Totalitarians, Populists... and oh yeah... any Statist of any kind. Of all philosophies in ethics there are two polars about interest, one of which is rational and one of which is irrational. There is Egoism and there is Altruism. Egoism has a controversial relationship with Individualism while Altruism has a controversial relationship with Collectivism. It's possible to be an Individualist and not be an Egoist yet it is not possible to be an Egoist and not be an Individualist. By that same token it's possible to be a Collectivist and not be an Altruist yet it is not possible to be an Altruist and not be a Collectivist.
The most rational ethical doctrine is Individualism and there's no doubt in my mind about that. However what I do question is whether it's more rational, less rational, or just as rational to be both an Egoist and an Individualist. That's not related to the subject really though, I'll spend time later attempting to figure it out or maybe you can discuss it with me later. My main assertion is that the most rational and also the most liberty aligned ethical doctrines is the Individualist doctrine. The Individual is important and I'll argue that self-interest is important which is the basic center of Egoism. Man is basically run by self-interest, he'll help his fellow man as any good man would but the self comes first. Even if he wants to think otherwise or asserts otherwise. It's even arguable that helping your fellow man is in self interest since you most likely get joy or a feeling of peace from such. He who is selfless is he who has no emotion, he has no soul, he is the primeval man.
The primeval man is arguably a killing machine, he kills outsiders who aren't with in his small, underdeveloped social circle. He is with the beat of nature, as nice as that sounds, remember that nature can be cruel. The highest murder rate in the world last I checked (which doesn't say much, I do invite you to check it out) is New Guinea which if you didn't realize is a very primitive country. They still practice cannibalism even though it's illegal. There are tribes in the Amazon which live in small social circles of between twenty and thirty people. Anyone outside of that social circle they kill and eat. They have little individual personality and don't have any form of knowledge, science, or philosophy. It's very absolute in this sense, you choose between the two. Collectivist, Primitivist, Hateful, Bloody, Anti-Intellectual, and of course... with out reason as the helmsman, Irrational. However the alternative is Individualist, Technologicist, Compassionate, Intellectual, and with reason as the helmsman, very rational.