It would seem as if a truly blind person (not just someone who is
partially blind, or "legally" blind, or became blind sometime in life)
would never be able to experience colors in the way that someone can
see does. Nonetheless, we can describe in words all about what colors
are.
Different wavelengths of visible light have different colors, and
mixtures of light of different wavelengths have different colors. A
blind person can feel the thermal energy deposited by light, and so can
be convinced that light exists and carries energy. Then it is just a
matter of description of what light is and its properties. I'm afraid
that for a blind man this may remain abstract and unverifiable, and he
may just have to take his friends' word for it all.
You can give a blind person a device that senses light and emits
sound or shakes or something, depending on the dominant color of the
light striking it. In that way, the blind person can explore what
colors are present when and where, but it still may be a bit of an
abstraction.
We do the same sorts of things in experimental science, since
there are lots of things we cannot directly sense with our eyes, ears,
nose, tongue and skin, but can sense with the aid of equipment. Such as
infrared radiation, X-rays, lots of colorless, odorless gases, and
other things.
Now that you mention it, there is a property of some elementary
particles which is whimsically called "color", which plays the role of
the electric charge, but for the strong nuclear force instead of the
electromagnetic force. Color isn't directly observable, so in a great
sense, we are all "blind" to this particular property. But it has lots
of observable consequences, so we are happy with the abstraction, even
if the name color is somewhat meaningless in this context.
Tom
(published on 10/22/2007)
