I mean, the existence of significant numbers of people who don't have "normal colour vision" is a pretty good indication that different perceptions of red is an

I mean, the existence of significant numbers of people who don't have "normal colour vision" is a pretty good indication that different perceptions of red is an actual thing. Seems far more childish to insist that that everyone's perception is either identical or impaired. If it is possible for human perception of colour using similar hardware to be so different that they subjectively experience 550nm and 700nm wavelengths as identical in appearance, it is surely possible for the minds of that people who can reliably distinguish between the two don't necessarily perceive them exactly the same way you do or I do. Apart from anything else, it would explain a lot of people's decorative choices! Even the "same hardware" argument doesn't stack up because even if it turns out you're actually my identical twin, our visual cortexes and brain structures and chemistry that parses, interprets, emotionally responds to and stores images evidently aren't the same.