are three different colors of dots because "normal" human color vision
has three different kinds of cones on the retina. If most people
were protanopic, our color monitors and TV's would have two different colors
of dots. The red dots wouldn't be needed. For a bird to see
on the monitor what it sees day to day, the monitor would have to have
four, five or six different colors of dots.
cannot have experiential knowledge of bird color. We are blind to
that bird-brain knowledge. It's beyond the edges of our comprehension.
However, we can, through mathematics, ask and answer meaningful questions
about what a bird sees. The answers we get cannot relate directly
to human experience, and we can be sure that those answers will be "simple
of science is like that: an attempt to peer beyond our evolution-developed
Stretch your knowledge
To understand what
white light is we must go beyond what we learned in grade school.
It's not that white light is simply equal intensities of three "primary
colors," or of all wavelengths, or even of all visible wavelengths.
Infrared and longer wavelengths
might be present, but our perception isn't affected by those wavelengths
which we can't see.
Ultraviolet and shorter wavelengths
might be present, and our eyes don't see those either, but ultraviolet
can, nevertheless, effect what we see in several ways. Ultraviolet
on our eyes can cause the corneas and lenses to fluoresce and put a haze
on the images we see. Ultraviolet causes many other things to fluoresce,
such as those bright orange detergent boxes in the supermarket. More
orange light comes away from the box than falls on the box. That's
to get your attention. "Whiter than white" is not just advertising
hype: If the detergent leaves a fluorescent substance in the laundry, the
whites will reflect more visible light than falls on them: they really
are whiter than white.
We can get equal responses from
each of the three cones with light that has virtually all of the
visible wavelengths removed. There are an infinite number of visible
wavelengths–light is a continuum [catch-22]
of wavelengths. Three wavelengths from that infinity are all that's
needed for us to perceive white, and those three do not have to
be those we learn in grade school as "primary" colors.
These are not facts that
fit those lessons from the third grade. These facts do show that
color is not simply a characteristic of the world around us, but also a
trait of the way we evolved to perceive and interact with that world.
Color can be better understood
if we learn about one very special solution to that puzzle of arranging
colors so that proximity and similarity correlate.
Meet the CIE chromaticity
diagram . . .
Throughout these Web pages you will see many unusual uses of color.
Are maps hard to read? So is the page on which the problem is introduced:
there, we used color to demonstrate one kind of difficulty of reading.
Does the thought of drowning in quicksand jar your senses? So does
the title of the quicksand page: there, we demonstrate the difference of
focusing planes for different colors to emphasize the point. But
the really unusual (perhaps it's even unique!) use of color is the demonstration
of one of the most pernicious and pervasive oversimplifications you will
see: the "scalar-reduction" of virtually all measures. It's
one of the symptoms of Herpes simpletonisus.