The discussion on human nature has left out the key point.
Man's nature is rationality and its innate affinity towards
a world of spiritual ideals. Yet the baser and coarser elements
of mankind are closer to the animal kingdom and are devoid of this
rationality.
Thus, the reason why there is an aristocracy, is because a lineage of
noble blood is not only full of the spirit that elevates it closer to
divinity itself in the great chain of being.
The lack of a hereditary aristocracy is a sign of barbarism in a society,
and a society
guided by leaders from the plebeian classes runs counter to the laws of
nature. Hence Cromwell and Robespierre, and the lack of good taste in
America 1996.
I would believe that Aristotle would extensively support me on these points.
:)