  Let us return to the issue of us having a yellow, purple and green striped sense datum or mental image and yet there being no yellow, purple and green striped thing in the brain. The identity theorist (Smart 1959) can say that sense data and images are not real things in the world: they are like the average plumber. Sentences ostensibly about the average plumber can be translated into, or elucidated in terms of, sentences about plumbers. So also there is having a green sense datum or image but not sense data or images, and the having of a green sense datum or image is not itself green. So it can, so far as this goes, easily be a brain process which is not green either.