This is a completely ridiculous statement. The lack of something doesn't imply it can't or won't exist, it just doesn't exist yet. The idea of liberty is relatively new and we're still learning.
Up until recently you could have made all sorts of arguments about the rights of women or minorities and how another form of segregation will settle into place -- because it's "natural"
People have tried building such societies many times: all have failed. The problem is that you've got ambitious humans and less ambitious ones. So how is it ridiculous to claim that a leader caste automatically appears in every situation? It doesn't have anything to do with gender or race. It's the simple fact that we are not born equal and have different abilities.
If you throw a bunch of mammals in a shared space, then generally a hierarchy and a 'ruling class' emerges. That is testable (and tested), and it is natural, literally, part of our nature. Now, wether it's unavoidable is a a different question, and wether its morally good is a yet different one; but it certainly is the natural order of things.
Orly, seriously? Find me the study that proves that for a group that is larger than a few million! Please just prove this point. It is sooo naive to just assume, "hey I saw 5 chick sand a hen, the hen ruled them, I think hundreds of millions of americans must be ruled by one hen too". Clever, clever... I am writing a scientific paper and just believe me (as you seem to believe easily, without proof) that Hierarchy is natural in small groups only, remember small groups. Absolutely NOT scalable!
I am sorry for my tone, sir. I didn't want to educate you or spray my opinion in your face. But please understand me, it drives me mad when people still believe that it's natural that the World, the Country, or the Cities must be ruled by one leader. To me it's as if somebody is truly believing that the earth is flat and want's to convince everybody else about that.
That statement said nothing about one person, but a ruling class. Look at every primate species. They all have a hierarchy of some fashion. Do you honestly believe that our ability to be really successful at breeding and exploiting the resources around us really make us exempt from natural selection?
Social hierarchies in apes and monkeys run a huge gamut of behaviors and structures. That a hierarchy exists doesn't say anything about social structure and how that hierarchy operates.
Up until recently you could have made all sorts of arguments about the rights of women or minorities and how another form of segregation will settle into place -- because it's "natural"