Imagine the following scenario. Instead of light rays, the page of text before me throws out a film consisting of a braille version of the page, which somehow reaches my eye (Lucretius has a similar idea, though without the Braille). Unlike light, this film is solid and can be felt. Inside my eye is a miniature finger that moves across the film until it finds the word it was looking for (for example ‘dog’).
Two questions: (1) what is the proximate object of my search? Is it the film itself, which the miniature fingertip is feeling its way across? Or is it the original text which emitted the film? (2) How actually is this different from the way that my fovea searches the retinal image? The image stays constant and fixed while my retina moves around it – rather as though the fingertip were attached to the eye, and I had to move the whole eye in order to move the fingertip.