Re: Why does blue green and red give the perception of almost every color?

Dear Sandra,
Your question is more far-reaching than it might seem at first glance. It  
relates less to the differences in physical nature of light vs. sound than 
to the way OUR BRAINS HAVE BEEN "WIRED" IN THE COURSE OF EVOLUTION. The 
creation of "almost all colors" by mixing just red, green and blue light 
rays does NOT OCCUR IN NATURE. It is a technical device used in TV- and 
computer screens, which was developed after many psycho-physical 
experiments had shown that it works, i.e. that for most colors, our brain 
cannot distinguish between single-wavelength rays and a suitably adapted 
mixture of red, green and blue. Why it cannot? Most probably because such  
a capability would not have brought a survival advantage to our forebears, 
since neither single-wavelength colors nor RGB colors occur in nature. The 
different stages of data reduction on the way from the eye (viz. the ear) 
to the brain have evolved so as to cope in the most efficient way with the 
demands of the natural environment. Lasers and TV have not had the time to 
influence the course of biological evolution. As to cultural evolution, 
that's an entirely different matter.. 
Best Regards
Werner Sieber