He weeps, for he has but one small tongue with which to taste a world
The images have a sour, battery taste and feel like the pelting of a hot summer cloudburst. They certainly convey some sense of where things are around me, but is that the same as sight?Whatever, says tongue-sight pioneer Paul Bach-y-Rita: "There's nothing special about the optic nerve. The brain doesn't care where the information comes from. Do you need visual input to see? Hell, no. If you respond to light and you perceive, then it's sight." Or perhaps, even more accurately, if you respond and perceive, who cares about the semantics? It certainly seems to be more like seeing than feeling; as someone who occasionally needs to communicate under the table in Morse code taps, I know how hard it is to translate mere touch into meaning, but the tongue electrodes bypass this laborious process. From the author's description, the bluky-tongue-held device allows you to respond to tongue transmissions without consciously translating them into information: "What the camera sees is zapped onto my tongue's wet, conductive surface. As Kamm rolls the ball, my blindfolded eyes see nothing, but a tingling passes over my tongue. When she sends the ball my way, my hand leaps out to the left. I've caught it."
In practical terms, the answer may be irrelevant. When Kamm places a small white cube somewhere on the table, I can reach out and grab it nine times out of 10, even though I'm blindfolded. I can even recognize large letters, as long as I can bob my head around to get a better sense of their outlines. Given a few more hours with the device, I might eventually learn to forget the tingling in my mouth and just see. Is that sight?
The idea of the brain's plasticity -- that brain functions aren't strictly compartmentalized, that the brain adapts to adversity and technology, that the swapping of jobs and abilities is not only possible but potentially commonplace -- is not a new one. But this makes me think about it from a slightly different angle. I wonder, for instance, whether this would be the last nail in the coffin of the "how could you evolve something so complex as an eye" argument. Not that scientific data is so useful for refuting that one, since if it were, there is ample evidence of the eye's evolution being more or less routine. Still, it kind of helps to show that the eye structure itself isn't even necessary to our visual perception. Could we survive even if they eye hadn't turned out exactly like it is? Well, yeah. What good is half an eye? Potentially lots.