It is time to come to the central conception of the Social Contract, the dogma which made of it for a time the gospel of a nation, the memorable doctrine of the sovereignty of peoples.  Of this doctrine Rousseau was assuredly not the inventor, though the exaggerated language of some popular writers in France leads us to suppose that they think of him as nothing less.  Even in the thirteenth century the constitution of the Orders, and the contests of the friars with the clergy, had engendered faintly democratic ways of thinking.[211] Among others the great Aquinas had protested against the juristic doctrine that the law is the pleasure of the prince.  The will of the prince, he says, to be a law, must be directed by reason; law is appointed for the common good, and not for a special or private good:  it follows from this that only the reason of the multitude, or of a prince representing the multitude, can make a law.[212] A still more remarkable approach to later views was made by Marsilio of Padua, physician to Lewis of Bavaria, who wrote a strong book on his master’s side, in the great contest between him and the pope (1324).  Marsilio in the first part of his work not only lays down very elaborately the proposition that laws ought to be made by the “universitas civium”; he places this sovereignty of the people on the true basis (which Rousseau only took for a secondary support to his original compact), namely, the greater likelihood of laws being obeyed in the first place, and being good laws in the second, when they are made by the body of the persons affected.  “No one knowingly does hurt to himself, or deliberately asks what is unjust, and on that account all or a great majority must wish such law as best suits the common interest of the citizens."[213] Turning from this to the Social Contract, or to Locke’s essay on Government, the identity in doctrine and correspondence in dialect may teach us how little true originality there can he among thinkers who are in the same stage; how a metaphysician of the thirteenth century and a metaphysician of the eighteenth hit on the same doctrine; and how the true classification of thinkers does not follow intervals of time, but is fixed by differences of method.  It is impossible that in the constant play of circumstances and ideas in the minds of different thinkers, the same combinations of form and colour in a philosophic arrangement of such circumstances and ideas should not recur.  Signal novelties in thought are as limited as signal inventions in architectural construction.  It is only one of the great changes in method, that can remove the limits of the old combinations, by bringing new material and fundamentally altering the point of view.