“We have defined art as the life form and aesthetic art as the life renewal: the stimulating, animating, agitating, inspiring, inspirational, fermenting, fascinating fanaticising, explosive and outrageous: the renewal of the unknown.”

Karel Appel – the complete sculptures,' (1990) not-paged

A Short History of Decay (1949)

Obituary in New York Times

remark in 1973; as quoted by Amy Flanagan in [file:///C:/Users/Fons/Downloads/The%20Subtle%20Emotive%3B%20Agnes%20Martin.pdf 'The Subtle emotive; Material and Experience in the Works of Agnes Martin'], essay redraft, 2015, p. 1
1970's

looking back to his early art-student years in Munich [c. 1903/4], when he was standing before the artdeco paintings of Leo Putz and Fritz Erler
undated
Source: Brücke und Berlin: 100 Jahre Expressionismus, Anita Beloubek-Hammer, ed.; Berlin: Nicolaische Verlagsbuchhandlung, Berlin 2005, p. 26 (translation: Claire Louise Albiez https://www.researchgate.net/publication/272168564)

Quote from 'Private Notebooks of Fritz Wotruba'; transl. Peter Foges & Haakon Chevalier – Neuchatel, Editions du Griffion, 1961.

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.

Emotional Architecture as Compared to Intellectual (1894)
Context: Man, by means of his physical power, his mechanical resources, his mental ingenuity, may set things side by side. A composition, literally so called, will result, but not a great art work, not at all an art work in fact, but merely a more or less refined exhibition of brute force exercised upon helpful materials. It may be as a noise in lessening degrees of offensiveness, it can never become a musical tone. Though it shall have ceased to be vulgar in becoming sophistical, it will remain to the end what it was in the beginning: impotent to inspire — dead, absolutely dead.
It cannot for a moment be doubted that an art work to be alive, to awaken us to its life, to inspire us sooner or later with its purpose, must indeed be animate with a soul, must have been breathed upon by the spirit and must breathe in turn that spirit. It must stand for the actual, vital first-hand experiences of the one who made it, and must represent his deep-down impression not only of physical nature but more especially and necessarily his understanding of the out-working of that Great Spirit which makes nature so intelligible to us that it ceases to be a phantasm and becomes a sweet, a superb, a convincing Reality.

The Age of Insight (2012)