yeah we got into that in philosophy once, i had a great professor, he said how to some people perceive red could be what i perceive as green and you'd never know because they see red and see green as well, but it might not be the same hue or shade


i had the idea of explaining the color, by putting up a light spectrum... red will feel warmer than blue and so on... green would be somewhere in the middle and not as warm, you could get them to feel green, then explain that certain things they have felt before are green, but im still not sure if that answer holds up