There are different shades of red that you can experience. You can distinguish between RED35 and RED36, two experiences of different shades of red. Both experiences of the two shades of red are more similar, phenomenologically speaking, between them that with regard to RED2.
Furthermore experiences RED35, RED36 and RED2 seem to be more similar that an experience of GREEN21. In general we distinguish between red experiences and green experiences. The phenomenal properties that characterize red experiences are in a sense different from those which characterize green experiences.
Do you think that it is controversial to suppose that red experiences have something phenomenological in common?
The former four experiences are in a sense similar, they are color experiences. They differ in a sense from visual experiences of forms, like a visual experience of a square. But again this experience and an experience of a red object have something in common: they are visual experiences, and in a sense the way they feel is similar.
Do you agree that visual experiences feel somehow similar and that the way that they feel is different from, say, auditory experiences?