Can a machine think

Turing judges the question "can a machine think?" too dependent on the use of words to be settled, and replaces it with a test, the imitation game: an interrogator converses blind with a human and a machine; if they can no longer tell them apart, there is no longer a reason to refuse to one what is granted to the other. To the objection that the machine would still lack consciousness of what it says, he answers that pressing it leads to solipsism: I know others think only by their behaviour, and refusing that same evidence to machines alone is arbitrary. The substrate therefore matters little, a universal machine being able to simulate any discrete-state machine.

"Computing Machinery and Intelligence", Mind (1950)

Chalmers argues that what carries experience is organizational invariance: it is functional organization that counts, not the matter realizing it. Replace your neurons one by one with chips of identical behaviour: either your experience would fade by degrees without anything in your behaviour betraying it, or it would vary while you swore nothing felt different. He holds both hypotheses to be absurd, and concludes that a silicon isomorph would have the same consciousness as you. His position here follows from no physicalism: it is because consciousness is for him a fundamental datum, tied to organization by a law of nature, that it tracks that organization whatever the substrate.

"Absent Qualia, Fading Qualia, Dancing Qualia" (1995) · The Conscious Mind (1996)

For Dennett, understanding is not an inner flash added to information processing: it is what a system does whose behaviour shows regularities fine enough that one gains by ascribing mental states to it, what he calls the intentional stance. Against the Chinese room, he replies that the man with the rulebook is only a cog: it is not he who would understand Chinese, but the whole system, room, rules and ledgers included. To seek in the brain a place where understanding would finally occur would be to reinstate the Cartesian theatre his work is spent dismantling.

The Intentional Stance (1987) · Consciousness Explained (1991)

The Chinese room: shut in a room, Searle manipulates Chinese symbols following a rulebook, and his answers pass for a speaker's, without his understanding a word. A program is only a syntax, a set of rules bearing on shapes; understanding further requires a semantics, a relation to the world that formal manipulation never supplies. Yet he does not conclude that only the living think: the brain is a machine, and an artefact reproducing its causal powers would think. What he refuses is therefore not the thinking machine, but the idea that running the right program suffices.

"Minds, Brains, and Programs" (1980)