CONCEPT
Functional Equivalence
The computational thesis that two systems instantiating the same input-output mapping are cognitively equivalent — the premise that makes the Turing test meaningful and that Chalmers's framework exposes as insufficient for consciousness.
Functional equivalence is the thesis that what matters about a cognitive system is its functional organization — the patterns of input, processing, and output it instantiates — and not the physical substrate that realizes the organization. On this view, if a silicon system and a biological system implement the same functional relations, they are cognitively equivalent. The thesis underwrites computational theories of mind and the Turing test. Chalmers's framework accepts that functional equivalence captures cognitive equivalence but insists it does not settle phenomenal equivalence: two systems can be functionally identical and phenomenally different.
In The You On AI Field Guide
The thesis has a distinguished pedigree running from Turing through Hilary Putnam's functionalism to contemporary computational cognitive science. Its force is that it explains how beings of radically different physical composition — humans, aliens, hypothetical AI — could share mental properties. If what matters is the pattern, not the material, then minds are multiply realizable, and the question of