Seeing is thinking
Art historians credit both Georges Braque and Picasso with the invention of Cubist painting because neither of the two friends would claim credit for himself. While Picasso subsequently passed through many phases of pictorial style, Braque continued ramifying his Cubist manner for decades.
A French critic coined the term "cubist" in pejorative description of the new way of composing pictures initiated by these artists in 1907. Limiting color and resolving forms into fragmentary planes, they devised ways to signify spatial relations among things in a picture without using perspective. For Picasso and Braque, perspective picture space was the basis of an idea of reality they could not hold. They suspected that, in terms of the viewer's attention, a painting is "realistic" at the expense of its true reality. And pictorial perspective is the traditional means of imposing the illusions of "realism" on a canvas surface. That is, perspective picture space is a means of taking the viewer's attention away from the objective aspect of a painting. Picasso and Braque invented a different kind of picture space, an optical space that does not "contain" subject matter in the traditional sense. Here subject matter is composed in such a way as to keep the constructed nature of a picture (the fact of its being a painting) before your mind. Braque wanted a painting's own existence, as thoughtfully processed matter, to be the idea of reality which it proposed. It was this capacity of painting to exemplify rather than represent reality that Braque spent his career exploring.
Braque never made completely abstract paintings, apparently because abstraction would throw too much weight on the literal aspects of a picture. He worked as if he believed that painting's address to questions about the real was something made possible by the tradition of representation. His repeated use of still life subjects was more than a choice of basic formats. Still life subjects are portable things, having more affinities with paintings themselves than any other category of subject matter. (Some of Matisse's still lifes incorporate views of other paintings by himself as subject matter.) An image is necessary to stimulate our curiosity or uncertainty about the relations between picture, painting, and reality.
In this 1921 still life, Braque eliminated much conventional drawing by painting the whole canvas black at the outset and building up the image with lighter tones. The intervals between areas of color consequently look like robust black lines (and not always outlines). By adding sand to the green of the grapes and running a comb through the ochre areas in imitation of wood-grain , he further modulates the painting's physical presence. By thoughtful composition, Braque endowed this modest still life with a powerful formal structure whose reality to the eye is meant to be in tension with the subject's reality for the mind.