metaphysicist

[Cross-posted.] 1. Defining the problem: The inverted spectrum Philosophy has been called a preoccupation with the questions entertained by adolescents, and one adolescent favorite concerns our knowledge of other persons’ “private experience” (raw experience or qualia). A philosophers’ version is the “inverted spectrum”: how do I know you see “red” rather than “blue” when you see this red print? How could we tell when we each link the same terms to the same outward descriptions? We each will say “red” when we see the print, even if you really see “blue.” The intuition that allows us to be different this way is the intuition of raw experience (or of qualia). Philosophers of mind have devoted considerable attention to reconciling the intuition that raw experience exists with the intuition that inverted-spectrum indeterminacy has unacceptable dualist implications making the mental realm publicly unobservable, but it’s time for nihilism about qualia, whose claim to exist rests solely on the strength of a prejudice. A. ATTEMPTED SOLUTIONS TO THE INVERTED SPECTRUM. One account would have us examine which parts of the brain are activated by each perception, but then we rely on an unverifiable correlation between brain structures and “private experience.” With only a single example of private experience—our own—we have no basis for knowing what makes private experience the same or different between persons. A subtler response to the inverted spectrum is that red and blue as experiences are distinct because red looks “red” due to its being constituted by certain responses, such as affect. Red makes you alert and tense; blue, tranquil or maybe sad. What we call the experience of red, on this account, just is the sense of alertness, and other manifestations. The hope is that identical observable responses to appropriate wavelengths might explain qualitative redness. Then, we could discover we experience blue when others experience red by finding that we idiosyncratic