Cosmopolitanism is an ancient creed; but in its modern form it was a creature of the Enlightenment attempt to create a new 'science of man', based upon a vision of humanity made up of autonomous individuals, free from all the constraints imposed by custom, prejudice, and religion. As Pagden shows, this 'new science' was based not simply on 'cold, calculating reason', as its critics claimed, but on the argument that all humans are linked by what in the Enlightenment were called 'sympathetic' attachments. The conclusion was that despite the many tribes and nations into which humanity was divided there was only one 'human nature', and that the final destiny of the species could only be the creation of one universal, cosmopolitan society.

This new 'human science' provided the philosophical grounding of the modern world. It has been the inspiration behind the League of Nations, the United Nations and the European Union. Without it, international law, global justice, and human rights legislation would be unthinkable. As Anthony Pagden argues passionately and persuasively in this book, it is a legacy well worth preserving - and one that might yet come to inherit the earth.