The snail movie plays to an empty house.
These experiments are fascinating, but they leave aside a larger question: what is a snail “seeing”? Do snails see as we do, with images of checkered cards appearing in their gastropod minds? Do they experience private displays of light and dark, processed by tangles of nerves into decisions, preferences, and meaning. The human body and the snail body are made from the same wet pieces of carbon and clay, so if consciousness grows out of this neurological soil, on what grounds do we deny the snail its mental images?
No doubt what it sees is radically different, an avant-garde movie of strange camera angles and lurching forms, but if the human cinema is caused by nerves, we have to allow for the startling possibility that the snails have a similar experience. But our culture’s preferred story is that the snail movie plays to an empty house. Indeed, the theatre has no screen. The snail has no internal subjective experience, we claim. Light from the eye’s projector merely stimulates the snail’s ductwork and wiring, causing the hollow theatre to move, eat, mate, and keep up the appearance of life.
(Source: The Forest Unseen: A Year’s Watch in Nature—David George Haskell)