Contract or Principles of Political Right , and the second title explains the first. Rousseau’s object is not to deal, in a general way, like Montesquieu, with the actual institutions of existing States, but to lay down the essential principles which must form the basis of every legitimate society. Rousseau himself, in the fifth book of the Emile , has stated the difference clearly. “Montesquieu,” he says, “did not intend to treat of the principles of political right; he was content to treat of the positive right (or law) of established governments; and no two studies could be more different than these.” Rousseau then conceives his object as being something very different from that of the Spirit of the Laws , and it is a wilful error to misconstrue his purpose. When he remarks that “the facts,” the actual history of political societies, “do not concern him,” he is not contemptuous of facts; he is merely asserting the sure principle that a fact can in no case give rise to a right. His desire is to establish society on a basis of pure right, so as at once to disprove his attack on society generally and to reinforce his criticism of existing societies.
Round this point centres the whole dispute about the methods proper to political theory. There are, broadly speaking, two schools of political theorists, if we set aside the psychologists. One school, by collecting facts, aims at reaching broad generalisations about what actually happens in human societies; the other tries to penetrate to the universal principles at the root of all human combination. For the latter purpose facts may be useful, but in themselves they can prove nothing. The question is not one of fact, but one of right.
Rousseau belongs essentially to this philosophical school. He is not, as his less philosophic critics seem to suppose, a purely abstract thinker generalising from imaginary historical instances; he is a concrete thinker trying to get beyond the inessential and changing to the permanent and invariable basis of human society. Like Green, he is in search of the principle of political obligation, and beside this quest all others fall into their place as secondary and derivative. It is required “to find a form of