The principle of functional invariance states that it is a natural law that conscious beings with the same functional organization have the same quality of conscious experience. A group of arguments in support of this principle are rejected, on the grounds that they establish at most only the weaker intra-subjective principle that any two stages in the life of a single conscious being that duplicate one another in terms of functional organization also duplicate one another in terms of quality of (...) phenomenal experience. (shrink)