Democracy, Aristotle says, arises from the belief that men who are equally free should be equal in all respects; oligarchy, from the fact that men who are superior in some respect claim too much. Both have a kind of justice, but not the best kind.
 Bertrand Russell, A History of Western Philosophy (1945). copy citation

Context

“In Greece, revolutions were as frequent as formerly in Latin America, and therefore Aristotle had a copious experience from which to draw inferences. The main cause was the conflict of oligarchs and democrats. Democracy, Aristotle says, arises from the belief that men who are equally free should be equal in all respects; oligarchy, from the fact that men who are superior in some respect claim too much. Both have a kind of justice, but not the best kind. “ Therefore both parties, whenever their share in the government does not accord with their preconceived ideas, stir up revolution ” (1301 ” ). Democratic governments are less liable to revolutions than oligarchies, because oligarchs may fall out with each other.” source