“Sane judgment abhors nothing so much as a picture perpetrated with no technical knowledge, although with plenty of care and diligence. Now the sole reason why painters of this sort are not aware of their own error is that they have not learnt Geometry, without which no one can either be or become an absolute artist; but the blame for this should be laid upon their masters, who are themselves ignorant of this art.”
The Art of Measurement (1525).
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Albrecht Dürer 6
German painter, printmaker, mathematician, and theorist 1471–1528Related quotes

Spoken in Prague, 1787, to conductor Kucharz, who led the rehearsals for Don Giovanni, from Mozart: The Man and the Artist, as Revealed in his own Words by Friedrich Kerst, trans. Henry Edward Krehbiel (1906).
Source: 1956 - 1967, Art-as-Art Dogma' part II, (1964), pp. 156-157

DoD News Briefing, Monday, April 28, 1997 - 8:45 a.m. EDT http://www.fas.org/news/usa/1997/04/bmd970429d.htm
Context: The mere fear that there is a mole within an agency can set off a chain reaction and a hunt for that particular mole which can paralyze the agency for weeks and months and years even, in a search. The same thing is true about just the false scare of a threat of using some kind of a chemical weapon or a biological one. There are some reports, for example, that some countries have been trying to construct something like an Ebola Virus, and that would be a very dangerous phenomenon, to say the least. Alvin Toffler has written about this in terms of some scientists in their laboratories trying to devise certain types of pathogens that would be ethnic specific so that they could just eliminate certain ethnic groups and races; and others are designing some sort of engineering, some sort of insects that can destroy specific crops. Others are engaging even in an eco- type of terrorism whereby they can alter the climate, set off earthquakes, volcanoes remotely through the use of electromagnetic waves.
So there are plenty of ingenious minds out there that are at work finding ways in which they can wreak terror upon other nations. It's real, and that's the reason why we have to intensify our efforts, and that's why this is so important.

Quote from 'On the Possibilities of Painting,' lecture, Sociétés des études philosophiques et scientifiques pour l'examen des idées nouvelles, Sorbonne, Paris (1924-05-15), printed in the Transatlantic Review, # 16 (June 1924), pp. 482-488; trans. Douglas Cooper in Horizon, # 80 (August 1946), pp. 113-122

Book Sometimes you win Sometimes you Learn

Letter to Nele van de Velde ((daughter of Henry van de Velde), Frauenkirch, 29 November 1920; as quoted in Letters of the great artists – from Blake to Pollock, Richard Friedenthal, Thames and Hudson, London, 1963, pp. 224-225
1920's

Translation from The Life of Pasteur p. 142 https://archive.org/stream/cu31924012227595#page/n155/mode/2up
Soirées scientifiques de la Sorbonne (1864)
Source: Nervous Stillness on the Horizon (2006), P. 12 (Gunter Brus inDie Schastrommel.Organ der österreichischen Exilregierung.Bolzano:ed. Gunter Brus,June 1972,no.8a, p. 57.)