Something that has interested me for quite a while. We are taught as we grow up that grass is green, the sky is blue and Guinness is black. We have names for colors, which are based on examples. However light does not have color and so how do we know that what I see as green someone else sees as pink. We all have the same examples to allow the naming but our experience may well be different. This may explain why some people have such god awful taste.