Fundamental

The thought keeps recurring that the science of vision has done itself a great disservice by conjuring up the idea that single cone receptors of the retina detect “color” as if they were some sort of completely self-contained laboratory spectrometer. This type of lazy mental construction has led, for example, to the introduction of such pseudo-scientific concepts as “intelligent design”. The actual situation is far simpler and fundamental. It is the appositional distance between two cones that detects the narrow wavelength directed to that specific area of the retina (i.e., the all-cone fovea) by the evolved, light refractive properties of the structure of the eye! For the case of cone-to-cone appositions, this wavelength, in addition to defining the actual long wave limit of the visual response, forms the “primary red” that leads (in conjunction with the other two geometric mid-band and short wavelength limit brightness peaks) to a synthesis of the many hues of “color” presented to the appropriate centers of the brain. I note that Edwin Land deduced this from measurements made external to the eye!
GCH