Krasny (1999)

A person with inverted spectrum colour blindness would see the whole spectrum of colours in exact reverse: all the colour contrasts and relationships would remain the same, and the condition would be in principle undetectable, unlike "normal' colour blindness. Various extreme philosophical conclusions have been drawn from this, such as the ideas that each of us must live in our own private sensory world, and we can never express the qualities of this sensory world to another person..