Art for Art's Sake

-as defined by 'The Penguin Dictionary of Literary Terms and Literary Theory' (4th ed.), J. A. Cuddon:

"The phrase connotes the idea that a work of art has an intrinsic value without didactic or moral purpose. This concept seems to have been first put forward by Lessing in ‘Laokoon’ (1766), and became something of an artistic battle-cry or slogan following the publication of Gautier’s Preface to ‘Mademoiselle de Maupin’ (1835). Throughout the 19^th century it became a guiding principle for many writers. Oscar Wilde was one of its leading advocates."