How about for purposes of this discussion we agree that we all pretty much agree that the world is 'real', not a fiction in the dream of some amorphous caterpillar in some unknown universe? And let's hold our discussion to what is normally seen by physiologically intact adult humans.
I assure you I wasn't trying to imply that the world might be a fiction in the dream of an amorphous caterpillar, but rather a fiction in our own dreams and imagination, to at least some extent.
The point I'm trying to make with this little excursion is how very, very difficult it would be to apply precisely defined terms to completely subjective experiences, given human variability.
On the matter of how we perceive color, we tend to assume that people are either color blind or not, and if they're not color blind, they will experience color exactly as we do. That's a bit like saying, you're either healthy or you're not, you're either tall or short, you're either fat or slim.
Common sense would tell me that the relatively few words we have (or at least use) for shades of green, for example, might indicate that uniformity of experience at even this basic level is not as great as we like to imagine, but we don't realise this because the terms we use for a particular colour are so broadly defined, like the word 'tension', that it gets us in the ball park.
When I first started using Photoshop, I was a bit mystified when attempting to increase the saturation of green foliage, using the Hue/Sat control and eyedropper, to discover that what I thought was green (would even swear was green) was in fact yellow or yellow 2, according to Photoshop.