Cosmopolitanism is the idea that all of humanity belongs to a single global community. Every human being was seen as a citizen of the world in his capacity of “reason” regardless of bloodlineage and racial origins. The thinkers of the Enlightenment, such as Kant, in the eighteenth century, embraced this idea. With the rise of Imperialism and Nationalism in the nineteenth century, however, cosmopolitanism was criticized as an unrealistic, utopian vision.