Steven Pinker -- How the Mind Works - Hampshire High Italian ...

The Mind's Eye | 217a fixed viewing position and copies the contours faithfully, down to thelast hair of the dog, a person who then views the painting from the positionof the painter would have his eye impaled by the same sheaf of lightrays that the original scene projected. In that part of the visual field thepainting and the world would be indistinguishable. Whatever assumptionsimpel the brain to see the world as the world and not as smearedpigment will impel it to see the painting as the world and not as smearedpigment.What are those assumptions? We'll explore them later, but here is apreview. Surfaces are evenly colored and textured (that is, covered withregular grain, weave, or pockmarking), so a gradual change in the markingson a surface is caused by lighting and perspective. The world oftencontains parallel, symmetrical, regular, right-angled figures lying on theflat ground, which only appear to taper in tandem; the tapering is writtenoff as an effect of perspective. Objects have regular, compact silhouettes,so if Object A has a bite taken out that is filled by Object B, A is behindB; accidents don't happen in which a bulge in B fits flush into the bite inA, You can feel the force of the assumptions in these line drawings,which convey an impression of depth.In practice, realist painters do not daub paint on windows but usevisual images from memory and a host of tricks to accomplish the samething on a canvas. They use grids made of wire or etched in glass, tautstrings running from the scene through pinholes in the canvas to a viewingreticle, the camera obscura, the camera lucida, and now the cameraNikon. And, of course, no painter reproduces every hair of the dog.Brush strokes, the texture of the canvas, and the shape of the framemake a painting depart from the idealization of Leonardo's window. Also,we almost always see a painting from a vantage point different from theone the painter assumed in front of his window, and this makes the sheafof light rays impaling the eye different from the one the real scene wouldsend out. That is why paintings are only partly illusory: we see what thepainting depicts, but we simultaneously see it as a painting, not as reality.The canvas and frame tip us off, and remarkably, we use these very cluesabout pjcturehood to ascertain our vantage point relative to the painting