The other day I was writing a review of Sue Donaldson and Will Kymlicka’s thought provoking new book Zoopolis: A Political Theory Animal Rights, and it got me thinking about Kant’s principles of cosmopolitan hospitality towards strangers. It strikes me that so much of what marks out our humanity rests in how we behave towards strangers. It’s easy to act with compassion towards those nearest and dearest to us, and it’s easy to wrongly favour those we love or identify with, but it is where doing the right thing is hard that the importance of morality comes often comes to the fore. Animals, it seems to me, are the ultimate strangers; they cannot and do not identify with us, or communicate as we do with each other. They cannot cry out from across the world for our help. Nor can they speak up and beg us us not to slaughter them. And this is why I’m beginning to think that animal rights theory should be thought of as beginning from a cosmopolitan expansion of universal human rights. Humanitarian principles should be principles that spring from our nature as moral beings – that are about being humane towards others rather than about simply protecting humans. Hopefully this post will act as the first steps in clarifying my thoughts prior to writing a paper on the cosmopolitan duty towards non-human animals.