9 Science Facts To Make You Sound Clever At Parties
2. "Blind People Don’t See Blackness, They See Nothing"
It has been said that blind people see with their eyes in much the same way as you see with your elbow: They just don't.
It's tempting for sighted folk to assume that blind people are plunged into a world of darkness. But this is coming from our very visually based brains. We're so dependent on visual stimuli that we simply cannot imagine its absence, replacing it instead with our idea of "black".
Blind people have never seen black and so don't know what it "looks like", just like if you were asked to imagine a completely new colour.
Asking a blind person what they "see" is a bit like a homing pigeon asking you how you perceive the Earth's magnetic field - you don't, you can't and you can't even begin to imagine what it would look like (without visualising some sort of colour).
We are, of course, talking about people who have been completely blind since birth. It is a slightly different matter with somebody who has lost their sight later in life.
What this second group of people see often depends on how they lost their sight. One guy who had his optic nerve severed describes what he now sees as "visual tinnitus" consisting of swirling colours and shapes that are constantly changing and often even distracting. The visual centres of his brain are still being constantly stimulated, just not from his eyes.