Two people sat at a blank table in a blank room are looking at a bouncy ball and they both agree that it’s red. Are they both seeing the same colour?
Yes, of course they are, because they’re both describing it as red.
There is no reason to suppose that they are observing the same colour. All of our categorisation of the world relies on language; the only way to communicate what we perceive to each other is through the use of language. At some point, someone decided to describe a lemon as yellow and it stuck, they pointed out the lemon to someone else and described it as yellow.
Now we all know lemons are yellow because we’ve been taught it since we were young but all that means is that we describe it in the same way, not necessarily that we perceive it in the same way. The word could easily mean something different to the two people in the room but it is all they have to try to communicate what they’re seeing.
If you taught a child that lemons are blue, they would associate the colour of a lemon with the word blue. It follows, then, that they would go on to describe other yellow objects as blue (chicks, sunflowers, buttercups etc.). The important thing isn’t which colour we see but the pattern that connects everything; a handful of grass is the same colour as a handful of limes (for the most part) whether we call it green, blue or black.
The two people sat looking at the ball both call it red but we have no idea what they’re actually seeing; all we know is that they’re using the same pattern to define their colours.
So, at the end of all of this, what colour is the ball? We don’t know. The ball may not even have a colour, perhaps the colour is entirely in our minds and not externally perceived.
Blip and Pop