This one chapter contains the gist of the Kantian moral philosophy, and makes it quite clear that Rousseau perceived its application to ethics as well as to politics. The morality of our acts consists in their being directed in accordance with universal law; acts in which we are guided merely by our passions are not moral. Further, man can only possess freedom when his whole being is unified in the pursuit of a single end; and, as his whole being can be unified only in pursuit of a rational end, which alone excludes contradiction, only moral acts, only men directing their lives by universal law, are free. In Kantian language, the will is autonomous ( i.e. prescribes to itself its own law) only when it is directed to a universal end; when it is guided by selfish passions, or particular considerations, it is heteronomous ( i.e. receives its law from something external to itself), and in bondage. Rousseau, as he says (Book I , chap. VIII