in reply to
Re^5: I'm not a PhD but...
in thread How many colors does a rainbow have?
I really do not understand why you would think that the colors would scintillate. Perhaps you are looking at the detailed mechanics that cones fire, recover, and fire again? In which case yes, persistence of vision is responsible for smoothing that out. And therefore reconstructs in our brain the impression of a constant mix of colours, which just happens to closely match the external reality of light that will create a continuous mix of reaction by our cones and rods. (Persistence of vision is famously responsible for allowing a sequence of still pictures to look like continuous motion - see your local television or movie for an example.)
Furthermore it certainly is the case to a reasonable approximation that a given frequency of light is the same colour. That's not exactly true because our perception of colour is mediated by whatever else we are seeing at the same time. This is necessary so that an object appears to remain the same colour as we carry it from a reddish indoor light to far more blueish outdoor light. As we do so the light we see changes substantially, but it still looks the same to us. But let's ignore that complication.
The important point is that I really don't understand why you think we should anywhere perceive pink in the rainbow. Particularly since I don't see it when I look at the rainbow.
Pink results from firing red and blue receptors without firing green. But given the response curves of our receptors, there is no frequency that does that because green responds strongest to colours between what red and blue respond to. This is is easily tested - just look at a rainbow. And when I do so, nowhere do I see pink. Which is exactly what theory tells me should happen.