“It is clear then that . . . those states in which the middle element is large, and stronger if possible than the other two [wealthy and poor] together, or at any rate stronger than either of them alone, have every chance of having a well-run constitution.” Thus did Aristotle summarise his analysis of the Greek city states. The stability of what we would now call “constitutional democracy” depended on the size of its middle class. It is no accident that the US and UK, long-stable democracies today succumbing to demagogy, are the most unequal of the western high-income countries. Aristotle, we are learning, was right. (See charts.)
“倘使中产阶级的人数超过其它两个部分（富裕阶级和贫穷阶级）之和，或仅仅超过两者之一，就可能建立一个持久的共和政体。”这是亚里士多德(Aristotle)分析希腊城邦国家之后得出的结论。我们现在所称的“宪政民主政体”的稳定性取决于其中产阶级的人数。并非巧合的是，美国和英国是西方高收入国家里最不平等的两个国家；二者都是长期稳定的民主国家，现在却被煽动性言论摆布。我们正在意识到，亚里士多德是对的。（参见图表）