The only stable principle of government is equality according to proportion, and for every man to enjoy his own.
 Aristotle, Politics (4th century BC). copy citation

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Author Aristotle
Source Politics
Topic equality government
Date 4th century BC
Language English
Reference
Note Translated by Benjamin Jowett
Weblink http://classics.mit.edu/Aristotle/politics.html

Context

“But the process may be reversed, and aristocracy may change into democracy. This happens when the poor, under the idea that they are being wronged, force the constitution to take an opposite form. In like manner constitutional governments change into oligarchies. The only stable principle of government is equality according to proportion, and for every man to enjoy his own. What I have just mentioned actually happened at Thurii, where the qualification for office, at first high, was therefore reduced, and the magistrates increased in number. The notables had previously acquired the whole of the land contrary to law;” source