Hence he comes to say that ruling and being ruled over by turns is an essential feature of constitutional government, which he admits as an alternative to aristocracy.

The end of the state, which is to be the standard of the distribution of political power, is conceived sometimes as a good for the apprehension and attainment of which "virtue" is necessary and sufficient (this is the principle of aristocracy), and sometimes as a more complex good, which needs for its attainment not only "virtue" but wealth and equality.

This latter conception is the principle on which the mixed constitution is based.

This in its distribution of political power gives some weight to "virtue," some to wealth, and some to mere number.

But the principle of "ruling and being ruled by turns" is not really compatible with an unmodified principle of "tools to those who can use them." Aristotle is right in seeing that political government demands equality, not in the sense that all members of the state should be equal in ability or should have equal power, but in the sense that none of them can properly be regarded simply as tools with which the legislator works, that each has a right to say what will be made of his own life.