We see it; we believe it!  And if we don't see it, it can be hard to believe.  Evolution gave us the equipment we see with.  But evolution didn't do a very complete job.  The better we understand our vision, and its limitations, the easier it is to believe—and use!—knowledge that's beyond the edges of (easy) human comprehension.


How do you know whether you are colorblind?
If you are colorblind, how do you comprehend what others see?

These interesting questions were addressed by a PBS series on psychology.  They depicted normal color vision (three-cone), total colorblindness, and two-cone colorblindness, with pictures like the following:

Normal color vision
Total colorblindness
Two-cone colorblindness
Do you see why...

we can be certain that the program writers and producers did not comprehend one of the critical characteristics of  colorblindness...and we are certain with "buzz-saw certainty."

The "dimensionality" of color vision was, for them, at the edge of comprehension, and possibly just a bit beyond.



What did the class discover when using the light kit (diffraction grating, filters, etc)?
  • Some light is composed of spectral lines (sodium lamp), some is composed of continuous spectra (incandescent lamp), some is a mix (fluorescent lamp).  (This is quantum mechanics revealing itself to us.)
  • The yellow filter transmitted no light in the yellow part of the spectrum.  It transmitted a narrow band in the green and a narrow band in the red.
  • Looking through the darker purple filter we see virtually no color distinctions; but looking through the lighter purple filter, many color distinctions are strikingly enhanced.  (Using the 846 filter, we can, in a sense, expand the dimensionality of our color perception.)
  • Haidinger's brushes, our weak perception of polarization, can be seen by holding the polarizers in front of our eyes and staring at a brightly lit, uniform light surface (the big projection screen).  (Many animals have excellent polarization perception.)
  • Light reflecting off non-metallic surfaces is polarized to a degree related to the angle of reflection.  Light reflecting off conducting  surfaces is not polarized by the reflection.  Polarized light reflecting off metallic surfaces remains polarized.  Polarized light reflecting off non-conducting surfaces does not retain its polarization.  (Newton was very uneasy about "action at a distance."  He simply couldn't accept the "logic" of action and reaction force, like that of the force between moon and earth, without something "carrying" that force.  We now know a third inseverable component accompanies the action and reaction forces: the "exchange particle."  Newton was right!  When we look at something, action - reaction pairs of forces exist between our eyes and the object observed.  The photons are the inseverable exchange particles--photons, because these forces are not gravitational, but rather electromagnetic.  The behavior of light reflecting from surfaces is an inextricable element of that interaction.  So, we are an inseverable part of the world we observe, but interpreting just what that means requires many-dimensioned, hyperlinked reasoning and careful avoidance of egocentric and anthropocentric wishful thinking.)