That the human mind has a certain order of possible progress, in which some things must precede others, an order which governments and public instructors can modify to some, but not to an unlimited extent: That all questions of political institutions are relative, not absolute, and that different stages of human progress not only will have, but ought to have, different institutions: That government is always either in the hands, or passing into the hands, of whatever is the strongest power in society, and that what this power is, does not depend on institutions, but institutions on it: That any general theory or philosophy of politics supposes a previous theory of human progress, and that this is the same thing with a philosophy of history.

Autobiography (1873)