---
date: '2025-11-10'
description: same function, different phenomenology
id: inverted spectrum
modified: 2026-06-05 15:08:05 GMT-04:00
seealso:
  - '[[thoughts/qualia]]'
  - '[[thoughts/functionalism]]'
  - '[[thoughts/philosophical zombies]]'
tags:
  - pattern
title: inverted spectrum
created: '2025-11-10'
published: '2025-11-10'
pageLayout: default
slug: thoughts/inverted-spectrum
permalink: https://aarnphm.xyz/thoughts/inverted-spectrum.md
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---
the inverted spectrum case asks whether two people could share functional roles while their color experience is swapped. Locke has the early version. Shoemaker makes the modern pressure test. \[@locke1689essay; @shoemaker1982invertedspectrum\]

the case only works if same function plus same public language leaves phenomenal character open. Hardin presses from color structure. Hue, saturation, brightness, and opponent relations constrain what a color experience can be. \[@hardin1988color\] Dennett presses the evidential criteria. If every use and discrimination is held fixed, it becomes unclear what evidence remains for the inversion. \[@dennett1988quining\]

the payoff for this cluster is narrow. Inverted spectrum is a stress test for [[thoughts/functionalism]]. It asks whether functional sameness entails phenomenal sameness.