The Necessity of Cosmopolitan Right

With regard to Kant's discussion of the unwritten code of cosmopolitan right, Gary asks: "Secondly, if this condition is necessary for the sake of public rights of human beings the question arises as to the sense of its necessity. What makes it so necessary?"


I see this as basically the question I asked with regard to international right: why does Kant think (in sec. 43 of the Metaphysics of Morals) that without all three levels of public right, the whole thing will collapse? In a footnote to section II of PP, Kant gives an answer: a state of war would still exist if one party were still in the state of nature. Rights would be insecure. I think a bit more can be said, and Kant sorta says them in cosmopolitan right, I guess. One thing Kant says that is that a violation in one part of the world is felt in everypart. The slave trade serves little ultimate purpose because it doesn't even make a profit, but it mediately involves training of sailors that go to war in Europe. Essentially, Kant is saying that unjust treatment of non-Europeans (non-states or less powerful ones outside the society of nations) will lead to war between Europeans. That is not the only way to read it, but I think it is part of it. Essentially, the issue is interdependence PLUS Kant's idea that we should come to terms with in law those who were unavoidably interact with. Once a violation of right in one DOES affect other people around the world, we need rules to regulate that interaction. "Private" wrongs become public wrongs, if they weren't before. (Consider what Kant says in the 4th preliminary article, about how when a country defaults on a national debt, this is a public wrong, as innocents everywhere are affected.)