Confined on the ship, from which there is no escape, the madman is delivered to the river with its thousand arms, the sea with its thousand roads, to that great uncertainty external to everything. He is a prisoner in the midst of what is the freest, the openest of routes: bound fast at the infinite crossroads. He is the Passenger par excellence: that is, the prisoner of the passage. And the land he will come to is unknown – as is, once he disembarks, the land from which he comes. He has his truth and his homeland only in that fruitless expanse between two countries that cannot belong to him.
Michel Foucault, Madness and Civilization: A History of Insanity in the Age of Reason