The retinal image is an image in a mathematical sense; it is a projection or a mapping. The retinal image is not an image in the sense of a picture – or, if it is, this is entirely accidental. How it looks, or how it reads, plays no role in its performance of its neurophysiological job description. Once we appreciate that the retinal image isn’t something that we see, we lose a grip even on what it means to say that it is upside-down. Upside-down, one must ask relative to what? Who’s to say what counts as upside-down in the head relative to the tasks faced by the nervous system?
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Again, we don’t experience the retinal image; we don’t experience any image , in that sense. We experience the world.
