to invert the spectrum from our perspective. This is because some small changes to the code used for displaying the world would make it so that it would display in red what was displayed in green before, etc., without changing the underlying simulated physics. Though this would entail that code on a computer which represents a creature with sight is equivalent with a creature with sight. It is not clear whether we can conclude from such examples that an inverted spectrum is possible in ordinary life. Inverted spectrum arguments have applications to behavioralism, physicalism, representationalism, functionalism, skepticism and the hard problem of consciousness. In his book I Am a Strange Loop, Douglas Hofstadter argues that the inverted spectrum argument entails a form of solipsism in which people can have no idea about what goes on in the minds of others—contrary to the central theme of his work. He presents several variants to demonstrate the absurdity of this idea: the "inverted political spectrum", in which one person's concept of liberty is identical to another's concept of imprisonment; an inverted "sonic spectrum" in which low musical notes sound like "high" ones and vice versa (which he says is impossible because low sounds can be felt physically as vibrations); and a version in which random, complex qualia such as riding a roller coaster or opening presents are reversed, so that everyone perceives the world in radically different, unknowable ways. See also Dualism (philosophy of mind) Functionalism Further facts Mary's room Ontological argument Philosophical zombies Philosophy of color Philosophy of mind Philosophy of perception Physicalism Qualia Subjective character of experience The map is not the territory Notes External links Stanford Encyclopedia of Philosophy David Cole Color Thought experiments in philosophy