“Only a radical cleaning of social and artistic life as, in the domain of art, is already done by Dada, which is anti-sentimental and healthy to the core, since it is anti-art. Only unscrupulously striking down any systematically bred amateurism in any field, can prepare civilization for the 'New Vision's happiness which is greatly and purely alive in a dew people.”

X magazine (1959-62)
Context: It is not necessary to subscribe to the tiresome conception of the artist as rampaging Bohemian to understand that the activity of painting is socially useless, or at best occupies a dubious position... In the remote purity of his solitariness, where the work of art is made, the artist is supremely the anti-social creature.

Jeff Koons in: Graeme Green. " 60 SECONDS: Jeff Koons http://metro.co.uk/2007/07/18/60-seconds-jeff-koons-532798/#ixzz3bThr2XKI," at metro.co.uk, 2007/07/18
1990s and later

Source: The Unbearable Lightness of Being

A Testament (1957)

What then must we do? (1886)

Source: Neither Left nor Right: Fascist Ideology in France, 1996, p. 268

quoted by Richard Kostelanetz and Joseph Darby (eds.) in Classic Essays on Twentieth-Century Music; Schirmer, New York, 1996 ISBN 0028645812
after 1916

Quote in 'Culture: Caspar D. Friedrich and the Wasteland', by Gjermund E. Jansen in Bits of News (3 March 2005) http://www.bitsofnews.com/content/view/154/42/
Variant translation: The heart is the only true source of art, the language of a pure, child-like soul. Any creation not sprung from this origin can only be artifice. Every true work of art is conceived in a hallowed hour and born in a happy one, from an impulse in the artist's heart, often without his knowledge. (as quoted in the article 'Caspar David Friedrich's Medieval Burials', Karl Whittington - http://www.19thc-artworldwide.org/spring12/whittington-on-caspar-david-friedrichs-medieval-burials)
undated
Context: The pure, frank sentiments we hold in our hearts are the only truthful sources of art. A painting which does not take its inspiration from the heart is nothing more than futile juggling. All authentic art is conceived at a sacred moment and nourished in a blessed hour; an inner impulse creates it, often without the artist being aware of it.

Steve Allen on the Bible, Religion, and Morality (1990)