What is functionalism, and why do people think it supports machine consciousness?

Accepted answer

1. PR Priya Raghavan 3 weeks ago

   ✓ Accepted answer Contributor

   Functionalism says a mental state is defined by what it does: its causal role. Pain is whatever state is typically caused by damage, causes distress and avoidance, and interacts with beliefs and desires in characteristic ways. What it's made of doesn't matter.

   That leads to multiple realisability, which Putnam pressed in the 1960s: the same mental state could be realised in neurons, in an octopus's very different nervous system, or in principle in silicon. If a machine had states with the right causal roles, it would have the same mental states, conscious ones included.

   The main objections target consciousness specifically:

   • Absent qualia. Ned Block's "China brain" (1978): imagine the population of China simulating a brain's functional organisation by radio. Would the whole thing feel pain? Many people think not.
   • Inverted qualia. Two systems might have the same functional organisation but different experiences, red for one where green is for the other.

   Functionalism is still the default in cognitive science, but many people accept it for belief and desire while doubting it for experience.

   1. PJ Pieter de Jong 3 weeks ago

      Contributor

      Clear and fair, thank you. So the move from "functionalism" to "machine consciousness" is valid, but only if functionalism holds for experience, which is exactly where it is most contested.