Contribution
It moves the inversion from inside the head to the world. The classic inverted spectrum asks us to believe a subject whose visual system was tampered with; Inverted Earth needs no tampering that the subject could notice, so the first-person report and physical supervenience both favour sameness of qualia, while intentional content and long-arm function invert. It also names a confusion on both sides of the debate: treating public contents like looking red as qualitative.
Key insight
Distinguish what an experience is about from what it is like. What it is about is fixed by what normally causes it and what it is used on, which can change without the brain changing; what it is like supervenes on the brain. Put a person in a world where causes and words are both inverted, and the first changes while the second stays put.
Assumptions
- Qualia realism = “there are intrinsic mental features of our experience” (p. 53).
- Two contents of experience (Shoemaker; Peacocke): intentional (representational) and qualitative (sensational), with “looks the same” in two senses (p. 54).
- Long-arm intentional content: intentional content is functional, with real things as inputs and outputs (p. 58); Harman agrees (pp. 58–59).
- Externalist shift of content with long embedding (Burge, Putnam; Davies’s Margaret Thatcher analogy, p. 64).
- Supervenience of qualitative content on physical constitution (pp. 65–66), and its asymmetry (p. 68).
- Empirical latitude: if human physiology blocks the case, a race very like us with colour sensations need not (pp. 57, 64).
Key results
- Fallacy of intentionalizing qualia (pp. 55–57). If inversion is rife, neither of us can claim our quale is the looking red; contents in public language are intentional and “Californian”, not neo-Fregean. McGinn and Peacocke, who define ‘red’ by “the” quale red things produce, commit it.
- Harman’s straw man (p. 59). Harman’s inverted spectrum inverts intentional contents; no proponent should accept that version.
- Intrapersonal inverted spectrum (pp. 60–61), in four stages; the crucial stage 3 testimony is attacked by Dennett (memory malfunction) and Rey. Block concedes “some justice” and changes tack.
- Inverted Earth (pp. 62–67). Intrapersonal: first day, intentional contents Earth’s and false; after fifty years, the natives’; functional states follow. Interpersonal: twins with molecular-duplicate brains, one raised there with lenses; the colour-matching game shows the functional inversion (strawberry and double-decker bus). Q = F₁, Q = F₂, F₁ ≠ F₂ contravenes transitivity of identity (pp. 64–65).
- Objection: Twin’s intentional content follows his qualia (pp. 68–69). It presupposes an inverted spectrum and commits the fallacy, so neither Harman nor the qualia realist can use it.
- Objection: other functional descriptions (pp. 69–71). Brain-internal descriptions make the twins identical, but cannot capture intentional content: clones with inverters at different angles get the same neural signal from red, yellow and blue. A functionalist could pair long-arm roles for intentional content with short-arm roles for qualia; the burden is to say what the latter are. A physiological theory “functionalized” changes the subject in a debate about computational identity (p. 71).
- Objection: inputs at the retina (pp. 71–72). Move the inverter behind the retina; for a sharply bounded sensorium, run the case on a being without one.
- Harman on introspection and Mary (pp. 72–75). Introspecting a blue wall cannot settle whether we are aware of intrinsic properties; complex cases can. On Mary, Harman’s reply concedes she gains intentional knowledge; the qualia realist says she gains two kinds, and on that Harman “is silent”.
- Notes 28–29. An absent-qualia argument would also doom a short-arm functional theory of qualia; “thought is functional, but … the best bet for a theory of qualia lies in neurophysiology”.
Claims
| id | claim | strength | support |
|---|---|---|---|
| C1 | Contents expressible in public colour words are intentional, not qualitative | moderate | p. 55, conditional on the possibility of inversion |
| C2 | On Inverted Earth qualitative content stays the same while intentional content and long-arm function invert | moderate | thought experiment, pp. 62–67; content shift rests on externalism |
| C3 | So no long-arm functional state is identical to a qualitative state | strong given C2 | transitivity, pp. 64–65 |
| C4 | Inverted Earth is a better argument against functionalism than the inverted spectrum | moderate | no internal switch, testimony, supervenience asymmetry, pp. 67–68 |
| C5 | A short-arm functional theory of qualia has not been given | burden-of-proof claim | pp. 70–71 |
| C6 | Introspection cannot settle whether we are aware of intrinsic features of experience | moderate as methodology | p. 73 |
Concepts
- Intentional / qualitative content — how the experience represents the world, versus what it is like (p. 54).
- Fallacy of intentionalizing qualia — taking contents expressible in public language to be qualitative (p. 55).
- Quasi-functional qualia realism — functionalism about intentional content and concepts, not about qualitative content (p. 58).
- Long-arm / short-arm roles — functional roles reaching to things in the world, versus stopping at the skin (p. 58).
Connections
- Harman, “The Intrinsic Quality of Experience” (same volume) is the target; Shoemaker’s “The Inverted Spectrum” supplies the two senses of “looks”.
- Dennett (LIT-433, NOTE-357) and Rey on intrapersonal inversion (n. 20).
- “Troubles with Functionalism” (LIT-407): the clumsier earlier version (nn. 21–22) and the neurophysiological bet (n. 29).
- “Functional Role and Truth Conditions” (LIT-625): long-arm roles are equivalent to short-arm roles plus reference (n. 26).
- Lycan’s Consciousness (1987) for “physio-functionalism” (n. 30).
Bearing on the record
- Chalmers’s organisational invariance (LIT-392, NOTE-347; LIT-406, NOTE-336) is a short-arm principle and is untouched by this argument; the two papers can both be right. The record should not cite Inverted Earth as a refutation of Chalmers’s principle.
- For THEORY-043’s functionalist premise: this paper grants functionalism for thought and denies it for qualia, the same split LIT-407 (NOTE-366, C6–C7) and “Advertisement” (LIT-648, p. 635) make.
- No instruction for machine-learning practice.
Limitations
- The content shift after fifty years rests on externalist intuitions some readers will not share; Block offers the interpersonal case for them.
- The empirical possibility of an undetectable inverter is assumed; the Harrison and Hardin asymmetry objections are rebutted only in a note (n. 17), and Block says the paper’s main claim survives them.
- Short-arm functionalism about qualia is not refuted, only challenged.
Open questions
- What would a short-arm functional characterisation of qualia look like, and does Chalmers’s invariance principle supply one?
- Do the subject’s long-term memories, which Block uses later against Lycan (“Mental Paint”, LIT-635), settle the gradual-shift reply here?