Loss of touch; there are rare cases of children who have no sense of touch. Unfortunately, they don’t typically survive into adulthood. Burns, broken bones, all meaningless to them. Bad stuff.
Being 1/2 blind, 1/2 deaf, I’ve straddled both worlds while attempting a semblance of ‘normal’. I’ve managed fine. Fully deaf? We’d manage. Fully blind? We’d manage.
Deaf and blind together would be trickier. That would result in a greater change of society. Our sense of “Where I am right now” and also our sense “How my body is positioned at present” would likely be heightened, as our mental maps of the areas would be much sharper and clearer as we couldn’t rely on backup senses of hearing (echolocation) or vision.
Sense of heat/cold would also increase, which would allow us a greater sense of where others are in relationship to ourselves. Our “personal space” bubble would be a keen sense indeed. I have a very keen personal space sense; I’m assuming its a sense of infrared changes, “seeing” the color of infrared with my skin as it were… which is why I know when someone’s behind me and such, and I know when someone is looking at me because more heat is escaping from their open eyes, causing me to feel the slight temperature differential with my skin on the back of my head.
Blindsight would increase as well. Our synthesthesia would likely be even more keen than it is at present, and the nature of language and communication would change.
I wonder if a fictional author has pursued ‘deaf-blind society’? That would be a good read, if it was hard sci-fi (the kind that tries really hard to be as scientifically accurate as possible) – not the sloppy sci-fi which I can’t really stand [unless there’s Time Travel. Then they can be really sloppy and I’ll still enjoy it]
Kenneth Udut I may be wrong about the infrared + eyes thing. I’m thinking it’s more to do with blindsight / sense of body-space-in-relationship-to-environment+positioning rather than strictly infrared.