 According to Blumenberg, metaphors of this kind, such as "the naked truth", are to be considered a fundamental aspect of philosophical discourse that cannot be replaced by concepts and reappropriated into the logicity of the 'actual'.The distinctness and meaning of these metaphors constitute the perception of reality as a whole, a necessary prerequisite for human orientation, thought and action.The founding idea of this first text was further developed in works on the metaphors of light in theories of knowledge, of being in navigation ("Shipwreck with Spectator", 1979) and the metaphors of books and reading.