"Cubist paintings were paintings by definition, that is, they are constructed by adhering paint to a surface (two-dimensional by definition) and as such fulfilled the requirements of entry to the category 'painting'. The controversy concerning Cubist paintings, was not primarily about wether or not they were (physically) paintings, but rather wether or not their form (in paint) was viable, Cubist collages were questioned on both levels."
January 1, 1970
https://en.wikiquote.org/wiki/Art-Language