“A real work of art destroys, in the consciousness of the receiver, the separation between himself and the artist.”

“An Unread Book”, p. 20
The Third Book of Criticism (1969)

From Dada Manifesto 1918 (23 March 1918) by Tristan Tzara
Misattributed

Donald Judd, in: American Dialog, Vol. 1-5, (1964), p. ix
1960s
Context: Any combining, mixing, adding, diluting, exploiting, vulgarizing, or popularizing of abstract art deprives art of its essence and depraves the artist's artistic consciousness. Art is free, but it is not a free-for-all. The one struggle in art is the struggle of artists against artists, of artist against artist, of the artist-as-artist within and against the artist-as- man, -animal, or -vegetable. Artists who claim their artwork comes from nature, life, reality, earth or heaven, as 'mirrors of the soul' or 'reflections of conditions' or 'instruments of the universe', who cook up 'new images of man' - figures and 'nature-in-abstraction' - pictures, are subjectively and objectively, rascals or rustics.

Vague Thoughts On Art (1911)
Context: Art is the one form of human energy in the whole world, which really works for union, and destroys the barriers between man and man. It is the continual, unconscious replacement, however fleeting, of oneself by another; the real cement of human life; the everlasting refreshment and renewal. For, what is grievous, dompting, grim, about our lives is that we are shut up within ourselves, with an itch to get outside ourselves. And to be stolen away from ourselves by Art is a momentary relaxation from that itching, a minute's profound, and as it were secret, enfranchisement. The active amusements and relaxations of life can only rest certain of our faculties, by indulging others; the whole self is never rested save through that unconsciousness of self, which comes through rapt contemplation of Nature or of Art.

As quoted by John Gery in Ways of Nothingness: Nuclear Annihilation and Contemporary American Poetry (1996)
Context: In each art the difficulty of the form is a substitution for the difficulty of direct apprehension and expression of the object. The first difficulty may be more or less overcome, but the second is insuperable; thus every poem begins, or ought to, by a disorderly retreat to defensible positions. Or, rather, by a perception of the hopelessness of direct combat, and a resort to the warfare of spells, effigies, and prophecies. The relation between the artist and reality is an oblique one, and indeed there is no good art which is not consciously oblique. If you respect the reality of the world, you know that you can approach that reality only by indirect means.

Nick Compton, Wallpaper* January 2017, p. 134

(1986) n.p.
Structures are no longer valid', in "Ein Gespräch..."

Art Psalms (2008), Seven Statements on Mystic Art