A more immediate influence of Rousseau's political thought was on the German philosopher Immanuel Kant, sometimes called "the philosopher of the French Revolution." Kant took over Rousseau's emphasis on the faculty of will and incorporated it into his political philosophy, especially in Part II of "The Metaphysics of Morals," "The Metaphysical Elements of Justice." There Kant, unlike Rousseau, favored a constitutional government rather than a direct democracy. But he utilized Rousseau's notion of the social contract in the form of a hypothetical agreement among autonomous individuals. Kant's conception of a hypothetical contract was in turn applied by John Rawls in his "A Theory of Justice," so it may be argued that Kant is in some respects a precursor of liberal representive democracy. Rousseau's idea of democracy has more application to contemporary theorists of participatory democracy than it does to Marx, whose "dictatorship of the proletariat" was largely undeveloped. And Mill's "On Liberty" is in many ways a critique of Rousseau's General Will, in that Mill asserted, among other things, that "if all of mankind except one were of one opinion, and that one were of another, all of mankind would be no more justified in silencing that man that would he in silencing all of mankind." So Rousseau's conception of positive freedom (i.e., "freedom to. . ."), encapsulated in his notorious remark that it may be necessary to "force men to be free," has no place in Mill's "On Liberty," which advances the more Anglo-American notion of negative freedom (i.e., "freedom from. . ."). Furthermore, Mill favored a form of representative government (as put forth in his treatise of the same name), so he differs from Rousseau on that point as well.