Colo(u)r sense

[JL]

There's lots of red herrings flying about, so let me attempt to clarify 
the 'artificial colour' thing as I see it.

The patented 'mauve' is not a colour. It's a substance, an artificial
dyestuff.  
As with most things, when illuminated with white light it reflects more than 
one wavelength.

The eye/brain perceives this particular combination of wavelengths as a 
single purplish colour.  Of course, this resultant colour 'mauve' does have 
an equivalent single-wavelength which exists in the normal visible spectrum.  
The argument seems to be whether this equivalent colour is
*naturally-occurring* 
(other than as part of the solar rainbow),  eg in a plant, or mineral, or
could 
simply never have been perceived before the invention of 'mauve'.  I can't 
see how this can be proved either way. 

If you want to get down the quantum level you can, no doubt, argue that 
the electromagnetic spectrum is not continuous.  In other words, there are 
only a finite number of possible Wavelengths in Nature (just as there are 
a finite number of possible Velocities, or Masses).  That you or I might 
somehow be able to 'fill in the gaps' with some interprative interpolation 
is a slightly spooky thought.  And utter tosh, I know.

JL
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 what's the frequency, kenneth?    [ - r.e.m. ]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~