But isn't blue (or red, green whatever) a distinct wavelength? So we will all see the same colour.
We could/do choose to label wavelengths of light with colour names, but I think colour itself is a concept manufactured in the brain, it's not a property of the "real world", it's merely an allusion to something in it. Just as two different people may not have the same experience/feelings about eating the same food, we can't say that two different people looking at the same wavelength experience it the same way.
The "real world" is unknown and unknowable, all we have is an idea of it created in our brain. This is of course somewhat shaped by what is out there, although most of our important knowledge of reality comes not from direct experience, but by a brain-washing process imposed on us by our elders, who pass down group knowledge via something called "education". So what we think of as reality is in many ways just a cultural construct.
Something mind-blowing I saw on Youtube recently is a scientist of some kind has proved that, in terms of perception, we are not adapted to see "reality" accurately/truthfully. Surprisingly, having you senses adapted to maximise accuracy of perception is not the same thing as having them adapted to see reality in ways that maximise your probability of survival.
The example he gave was this: imagine a world where oxygen varies from place to place, an organism needs oxygen levels in the range 19% to 22% to thrive. One organism see the colour green when oxygen levels are in the range 0% to 50%, and the colour red for the range 50% to 100%. Another organism see green for the range 19%-22% and red everywhere else. The first organism will have a better comprehension of reality, but will become extinct, because it will be out-competed by the one that knows exactly where it needs to go, even though it knows nothing about the rest of the world.