Hospitality, Kant insists, is not a matter of charity or courtesy — it is a right grounded in the fact that the earth's surface is shared by all human beings. No one has an original claim to any particular part of it, so every person has a right to attempt to enter into community with others wherever they may be. The duty of hospitality flows from this common possession, not from humanitarian sentiment.
Universal hospitality does not include the right to permanent settlement or to commercial exploitation. The visitor has a right not to be treated as an enemy upon arrival; but the host state may refuse entry if this can be done without destroying the visitor. Kant explicitly criticises European colonial powers, which used the pretence of hospitality and trade to conquer and subjugate entire peoples.
Universal hospitality represents a third sphere of law, beyond civil law (within states) and international law (between states): cosmopolitan law, which governs relations between individuals across state boundaries. The three spheres together — republican constitutions, the federation of states, and cosmopolitan law — constitute the full legal framework that perpetual peace requires.
The Third Definitive Article and the cosmopolitan right are discussed in Section Two of Perpetual Peace; the critique of colonialism appears in the Second Supplement.
