Block’s Inverted Earth
Block imagines a Twin Earth like ours, but with two differences (Block 1990). Firstly, colors are inverted: grass is red, tomatoes are green, and so on, for the rest of the color spectrum. Secondly, color terms are inverted, so red grass is said to be green, green tomatoes are said to be red, and so on. Imagine now that devious scientists use you for an experiment. After giving you general anesthesia, they put— unknown to you—color-inverting lenses in your eyes and take you to Inverted Earth, where you wake up believing you are on Earth. The colors are inverted, but you are wearing color-inverting lenses, so you don’t notice anything odd. Since people use inverted color vocabulary, their talk about colors is the same. Nothing seems different.
Suppose you look at a tomato on Inverted Earth and think “a nice red tomato.” Block believes that your perceptual experience has both representational and phenomenal properties. At first, you represent the tomato falsely because the tomato isn’t red—not where you come from and with respect to your background. However, as time goes by, you adapt to the linguistic community. Suppose you live there for years and then look at a tomato and think “a nice red tomato.” Block believes that now you represent the tomato correctly. Why? You have adopted the color representational scheme and vocabulary of the Inverted Earth community. However, your qualia are the same: phenomenally speaking red is the same old red. If we agree with Block, we would have to say that qualia cannot be supervening upon represen?tational properties, because the representational properties changed, while the phenomenal properties did not.
Block believes in what externalists call “wide content” with respect to representational contents. Representational contents need to be understood in a wide manner, in relation to the environment that a person is situated in and has been historically situated in. But he believes in narrow content with respect to phenomenal contents: they are narrow—possessed by an individual and located in the head—not differentiated by the world outside.