Iure Gentium hoc introductum est, ut cunctis hominibus inter se libera esset negotiandi facultas, quae a nemine posset adimi.[147a] Et hoc, sicut post dominiorum distinctionem continuo necessarium fuit, ita originem videri potest antiquiorem habuisse. Subtiliter enim Aristoteles μεταβλητικὴν dixit, ἀναπλήρωσιν τῆς κατὰ φύσιν αὐταρκείας,[148a] hoc est, negotiatione suppleri id quod naturae deest, quo commode omnibus sufficiat. Oportet igitur communem esse iure gentium non tantum privative, sed et positive, ut dicunt magistri, sive affirmative.[149a] Quae autem illo modo sunt iuris gentium, mutari possunt: quae hoc modo, non possunt. Id ita intelligi potest. Dederat natura omnia omnibus. Sed cum a rerum multarum usu, quas vita desiderat humana, locorum intervallo homines arcerentur, quia ut supra diximus, non omnia ubique - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - CHAPTER VIII _By the Law of Nations trade is free to all persons whatsoever_ If however the Portuguese claim that they have an exclusive right to trade with the East Indies, their claim will be refuted by practically all the same arguments which already have been brought forward. Nevertheless I shall repeat them briefly, and apply them to this particular claim. By the law of nations the principle was introduced that the opportunity to engage in trade, of which no one can be deprived,[147] should be free to all men. This principle, inasmuch as its application was straightway necessary after the distinctions of private ownerships were made, can therefore be seen to have had a very remote origin. Aristotle, in a very clever phrase, in his work entitled the Politics,[148] has said that the art of exchange is a completion of the independence which Nature requires. Therefore trade ought to be common to all according to the law of nations, not only in a negative but also in a positive, or as the jurists say, affirmative sense.[149] The things that come under the former category are subject to change, those of the latter category are not. This statement is to be explained in the following way. Nature had given all things to all men. But since men were prevented from using many things which were desirable in every day life because they lived so far apart, - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - proveniunt, opus fuit traiectione; nec adhuc tamen permutatio erat, sed aliis vicissim rebus apud alios repertis suo arbitrio utebantur; quo fere modo apud Seres dicitur rebus in solitudine relictis sola mutantium religione peragi commercium.[150a]