“My belief is that art should not be comforting; for comfort, we have mass entertainment and one another. Art should provoke, disturb, arouse our emotions, expand our sympathies in directions we may not anticipate and may not even wish.”

"Peace and Violence" (1973).

The Guardian [UK] (28 July 1989)

Games for Actors and non-Actors (1992)
Context: Wouldn’t it be wonderful to see a dance piece where the dancers danced in the first act and in the second showed the audience how to dance? Wouldn’t it be wonderful to see a musical where in the first act the actors sang and in the second we all sang together?... This is... how artists should be—we should be creators and also teach the public how to be creators, how to make art, so that we may all use that art together.

The Notebooks of Leonardo da Vinci (1883), X Studies and Sketches for Pictures and Decorations

Source: Naked

1951 - 1968, The Creative Act', 1957
Context: I want to clarify our understanding of the word 'art' – to be sure, without an attempt to a definition. What I have in mind is that art may be bad, good or indifferent, but, whatever adjective is used, we must call it art, and bad art is still art in the same way as a bad emotion is still an emotion.
Therefore, when I refer to 'art coefficient', it will be understood that I refer not only to great art, but I am trying to describe the subjective mechanism which produces art in a raw state – 'à l'état brute' – bad, good or indifferent.

Source: Shades of Milk and Honey (2010), Chapter 4 (p. 54)

RTNDA Convention Speech (1958)