In Western philosophy we have a very long tradition of cosmopolitanism. Its age is reflected in the fact that the word "cosmopolitanism" comes from a Greek phrase that was first used in the fourth century before the Common Era, probably by Diogenes the Cynic, kosmopolitês (citizen of the world).
What's amazing is that that notion was invented before it could possibly make any sense. For a shared sense of citizenship to make sense, you have to know about each other and you have to be able to affect each other. Diogenes was not in a position to know about most of the people in the world. He knew nothing about the people who were living in what we call Latin America. He didn't know anything about East Asia. Herodotus thought the world stopped just the other side of India. But, nevertheless, he imagined this thought that we could all be citizens of one thing.
So there has been a very long discussion of this idea. It has waxed and waned. But in the course of that discussion, I think a couple of really good ideas have developed that are now really useful in the context of our new global situation.
One is this basic idea that we do have responsibilities to everybody, that the boundary of your state is not the boundary of your moral concern. That's the universal side of cosmopolitanism.
The other side of it is that cosmopolitanism has always -- at its best, anyway -- combined the respect for universality with the recognition that there are forms of difference that should be allowed to persist, that not everybody has to be the same in order for the world to be going well, going right.
In the sort of aesthetic dimension of cosmopolitanism, that goes with the thing that is called cosmopolitan in the arts, which is an engagement with the cultural and literary and poetic and artistic life of other societies.
So these things are all connected by the thought: We're all one thing, we're all a single community; on the other hand, we have forms of difference that are ok. We don't want everybody to become the same. It's actually part of the joy of being human that you know that there are other humans who are doing it in different ways.
That basic background framework means that you are in a good position both to participate in the global moral conversation as someone who thinks that it's important that we're all one community, but also to participate in a way that might actually draw other people in because the other people you are drawing in are not being told, "Ok, we have all the answers; the way we do it is the only way to do it -- my way or the highway." Rather, what you are saying is, "Look, there are things we have to agree on that are basic, that are human rights, and we don't compromise on those. But beyond that there's a wide range of things where it's up to each human being and each community of human beings to make up their own minds about how they are going to do it."
Cosmopolitans are tolerant enough of difference that we know that some people aren't cosmopolitan. So we accept that not everybody is going to be on our side on this, especially on the difference side. I think we are morally obliged to tolerate difference, and so that's part of the universal bit. But you're not morally obliged to celebrate it. If you want to be an Amish person and live in the closed community that is self-consciously uninterested in what's going on outside because you are focused on the moral life of your own community, that's one of the things that the cosmopolitan says you are allowed to do, provided you do your duty to everybody else.
This post was produced by The Huffington Post and Carnegie Council for Ethics in International Affairs as part of the Council's Centennial Thought Leaders Forum. The series features thought leaders answering questions posed by Carnegie Council Senior Fellow Devin Stewart. For more information about the Carnegie Council, click here.