Apart from Kant's narrow and rigid logic, it is essentially one with his doctrine of the autonomy of the will. The germ of mis application is already found in Rousseau's own work; for he protests more than once against attempts to treat moral and political philosophy apart, as distinct studies, and asserts their absolute unity. This is brought out clearly in the Social Contract (Book I, chap, viii), where he is speaking of the change brought about by the establishment of society. "The passage from the state of nature to the civil state produces a very remarkable change in man, by substituting justice for instinct in his conduct, and giving his actions the morality they had hitherto lacked. What man loses by the social contract is his natural liberty and an unlimited right to everything he tries to get and succeeds in getting; what he gains is civil liberty . which is limited by the general will. We might, over and above all this, add to what man acquires in the civil state moral liberty, which alone makes him truly master of himself; for the mere impulse of appetite is slavery, while obedience to a law which we prescribe to ourselves is liberty."
In Kantian language, the will is autonomous (i
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.