Perception of red can be inverted, or redefined, anywhere in the chain that is perception, including before or after the retina.

Click on the 5. “Perception Inverted” section of this video, to see this problem illustrated.

 

 

The only difference between these two people is they have a red green inversion, somewhere in the chain of events that is their perception.

So how do you define the quality of 700 nm light?  Based on the quality of the knowledge of the person on the right, or the knowledge of the person on left?

The only reason we define a 'red' intrinsic quality according to light, is because that is the last point in the chain of perception that is easily invertible, before it gets into the body.

 Brent