Figure 9.1 A case of inverted phenomenology2.5 Real inversions?Unfortunately for the above line of reply to Chalmers, there are variants of
the inverted-spectra arguments (but not of the absent-qualia arguments)
which seem to show that undetectably inverted phenomenologies are not
just conceivable, butnaturallypossible – in which case it cannot be
metaphysically necessary that all percepts of red are similar in respect of
feel. Here, for example, is a possible case of intra-personal spectrum
inversion (Shoemaker, 1981; Block, 1990):
(1) We take a normal person and insert colour-inverting lenses into his
eyes (or we insert a neural-transformer into his optic nerve, which
transposes the sort of neural activity normally characteristic of seeing
red, into the sort of activity normally characteristic of seeing green,
and so on round the colour-circle). He says that grass looks red and
blood looks green.
(2) After a period of confusion and deviant usage, the person brings his
colour-concepts into line with the rest of us – for example, he says (and
thinks) that grass is green and that blood is red. But he stillremembers
that grass used to look the way blood now looks to him.
(3) Everything remains as in (2), except that he undergoes amnesia. Then
we have someone who is functionally indistinguishable from a normal
person. But surely what colour-experience islikefor him is still inver-
ted from normal – in which casewhat it is likecannot be functionally
characterisable.
Some people respond to this sort of argument by saying that the case is
Mysterianism 243