Up for grabs is whether "things as they are" are to be understood in naturalistic terms (a tree is a tree) or in idealist or perspectival terms (a tree reduces to the various tree-perspectives) or Kantian terms (there is something, whatever it is, that is responsible for the tree, or the various tree-perspectives: Kant's "ding-an-sich"). The tree in "Of the Surface of Things" poses an interesting test of such philosophical interpretations. Also there is a moment in Stevens' poetic development when he realizes that the polarity of things as they are and things imagined is not safe, when red bleeds into blue in "Anecdote of the Prince of Peacocks", Stevens' brutal encounter with Berserk. (See also "The Cuban Doctor" for a comparable encounter with the Indian.)