I do not believe that art must develop on national lines, but I am convinced that there never was and never will be an international art. There is and was French, German, Italian, and Flemish art. But I deny those specific definitions so fashionable with adepts of fascism which make of every country an hermetic cell from which all foreign artists are excluded.

1944, in New York. Artists on Art – from the 14th – 20th centuries, 1972, p. 430