This peculiar thinker - although often described as irrationalist or romantic - also latched on to and deeply depended on Cartesian thought. Rousseau's heady brew of ideas came to dominate 'progressive' thought, and led people to forget that freedom as a political institution had arisen not by human beings 'striving for freedom' in the sense of release from restraints, but by their striving for the protection of a known secure individual domain. Rousseau led people to forget that rules of conduct necessarily constrain and that order is their product; and that these rules, precisely by limiting the range of means that each individual may use for his purposes, greatly extend the range of ends each can successfully pursue.
It was Rousseau who - declaring in the opening statement of The Social Contract that 'man was born free, and he is everywhere in chains', and wanting to free men from all 'artificial' restraints - made what had been called the savage the virtual hero of progressive intellectuals, urged people to shake off the very restraints to which they owed their productivity and numbers, and produced a conception of liberty that became the greatest obstacle to its attainment. (...) The admittedly great seductive appeal of this view hardly owes its power (whatever it may claim) to reason and evidence. (...) Despite these contradictions, there is no doubt that Rousseau's outcry was effective or that, during the past two centuries, it has shaken our civilisation. Moreover, irrationalist as it is, it nonetheless did appeal precisely to progressivists by its Cartesian insinuation that we might use reason to obtain and justify direct gratification of our natural instincts.
Jean-Jacques Rousseau