QuestionsCan a machine think?Does a submarine swim? A question of decision about a word, not of fact
Can a machine think?An ill-posed question

Does a submarine swim? A question of decision about a word, not of fact

Do submarines swim? (Chomsky)

Noam Chomsky born 1928Linguist who studies language and mind as natural objects, and finds the question "can machines think?" empty.
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What it claims

The question "can a machine think?" is ill-posed: it is not a question that an experiment, such as the Turing test, can answer.

Why

Asking if a machine thinks is like asking if a submarine swims: we choose how to extend a word, there is no fact to find.

The same idea through history
Alan Turing1950Turing judges the question "Can machines think?" too meaningless to deserve discussion and expects the use of words to change.Edsger W. Dijkstra1984Dijkstra writes that the question is about as relevant as whether submarines can swim.
Noam Chomsky1996Chomsky, in Powers and Prospects, turns the image into an argument: these are questions of decision about extending a word, not of fact.
In short

"Does a submarine swim? A question of decision about a word, not of fact" is an argument by Noam Chomsky (Powers and Prospects, 1996, 1996) on the question "Can a machine think?" (answer: an ill-posed question). Its claim: The question "can a machine think?" is ill-posed: it is not a question that an experiment, such as the Turing test, can answer. According to AskPhilosophy's logic check (Z3 solver), the argument is valid only if one grants a premise the author leaves unstated (P4). AskPhilosophy presents 3 objections, 1 of them with a documented reply, and the original text behind each premise, checked word for word.

Powers and Prospects, 1996
Valid with an implicit premise

In a chapter of Powers and Prospects (1996), the linguist Noam Chomsky criticises a popular approach to artificial intelligence: the Turing test, which tries to decide whether an object "manifests intelligence". For him, whether a computer plays chess, understands Chinese or thinks is like whether robots can murder or airplanes can fly: a matter of decision, not of fact. A submarine mistaken for a whale does not show that it swims, nor that it does not. Chomsky argues that Turing himself understood this. A caveat: a spoken remark by Chomsky about Japanese (where a submarine would be said to swim) is sometimes cited; we have not found it in any verifiable text and do not use it.

P1Whether a computer plays chess, translates Chinese or thinks is like whether airplanes fly or submarines swim.
P2Such questions are questions of decision, not fact: it is a matter of whether to adopt a certain metaphoric extension of common usage. For the submarine, all agree there is no fact to establish.
P3Turing himself noted that the question "can machines think?" is too meaningless to deserve discussion, and expected usage to change, as for "flying" in English but not "swimming".
P4 · implicit premiseBehind the choice of the word "think" there is no other question of fact to ask about the machine: everything comes down to a decision of vocabulary.
Therefore the question "can a machine think?" is ill-posed: it is not a question that an experiment, such as the Turing test, can answer.

click a premise to reject it

If you accept every premise, logic forces you to accept the conclusion. So the debate is about the premises.
Checked by a logic solver: the premises cannot all be true while the conclusion is false.
Without the implicit premise: Without P4, the computer finds a case where the word "think" is a matter of decision, but a real question of fact remains about what the machine experiences: the question is not empty after all.
Valid with P4. This hidden premise is what the objections attack: they hold that behind the word there remains a question of fact (understanding, lived experience). Chomsky's argument targets the Turing test: it does not rule out studying scientifically how minds or programs work.
Analogy. An airplane "flies", a feather "flies", time "flies". Where does real flight begin? No experiment can say: one must choose a use of the word. Chomsky himself cites the airplane and the submarine; the rest is ours.

Objections

3

Each objection is a conversation: click to see who replies and where the debate stands.

Alan Turing 1950 · attacks the conclusion

Turing does not merely set the question aside: he replaces it with another, "closely related and expressed in relatively unambiguous words", the imitation game. This new question is one of fact: can a program fool an interrogator as often as a man? The test would thus answer something precise.

Chomsky replies
see the argument
Noam Chomsky 1996 · Chomsky's reply
Chomsky answers that the resemblance with the Cartesian test, which sought to determine whether an object has the property of having a mind, is misleading. Descartes's experiments were like a litmus test for acidity; this is not so for the AI debate.
The debate goes on (our summary) Supporters of the test answer that the imitation game measures a precise performance, which suffices for an engineering science. Chomsky does not deny it: he denies that it answers the question "does a machine think?" (our summary).
Where the debate stands (our summary)The disagreement is about what the Turing test measures: a performance (what Turing proposes) or a property of the machine (what Chomsky says it does not measure). Both camps agree that the original question is vague (our summary).
John Searle 1980 · attacks premise 4

The question of understanding is not a question of words. A computer following a program manipulates symbols without knowing what they mean: it has syntax, not semantics. Whether a program suffices for understanding is, for Searle, "the right question to ask".

no reply
see the argument
We have not yet found a direct reply by Chomsky in the texts.
Where the debate stands (our summary)Chomsky does not answer Searle in the passage read. Some hold the question of understanding to be real and distinct from that of words; others hold that "understand" is also a word we extend. No consensus (our summary).
David Chalmers 1995 · attacks premise 4

Even if we set aside the words "think" and "understand", a question remains that is not verbal: is there something it is like to be this machine? Chalmers speaks of "the really hard problem", that of experience.

no reply
see the argument
We have not yet found a direct reply by Chomsky in the texts.
Where the debate stands (our summary)Open point: Chomsky does not discuss consciousness in the passage read. Some hold the question of experience to be real and distinct from words; others think it will vanish with a better science of the brain (our summary).