B The Redness of Red: fact or fiction?

[Dr Wu]

This question has been bothering me for sometime now: do we actually see colours? The colour red, for instance, has the frequency of 650nm, but does this explain its "redness" as experienced by humans? Many neuroscientists suggest this is just a phantom, that colours are subjective constructs, nothing more. What do physicists think?

And what about this?

https://www.theguardian.com/technol...lour-illusion-the-dress-blue-black-gold-white

 

[elcaro]

Light has only the property of frequency and polarisation, there is physically nothing "red" about light. How our brain processes the incoming signals from our eyes is something totally different, these are neuro signals processed by the visual cortex.

 

[tech99]

It looks as if the eye has RGB sensors and just compares the output of each. People with colour deficiency have differing sensitivities of these sensors, yet may describe what they see by colour names. No doubt the brain does not care what the actual sensitivities of the sensors are and just compares the three signals.

 

[Dr Wu]

Yes, this makes a lot of sense to me too. It was just that a well-known science writer expressed some doubts about it in a book review forum recently, which left me wondering in turn. Thanks for the input.