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Chapter4.3_TheRussianroomargument-revisedfor3rdedition.ppt

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Chapter 4.3:
The Russian room argument

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

Lines of attack

Frame problem

Presents difficulties for the idea of representing knowledge symbolically

Russian room argument

Challenges the syntactic assumption at the heart of the PSSH

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

Frame problem

Original version (McCarthy and Hayes 1969)

How can a formal system represent the changes brought about by an action without explicitly representing all the things that the action does not bring about?

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

Broader versions of frame problem

Some theorists have argued that the frame problem poses an in principle objection to the PSSH

• (Alleged) impossibility of formalizing commonsense reasoning

• Often accompanied by emphasis on “situatedness” and “embodiment” of real cognitive agents

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

Assessment?

It is hard to know how to assess these arguments without explicit impossibility proofs

The real test comes with the alternative models proposed

Connectionist models of knowledge representation

Embodied/situated AI

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

Syntax

Physical symbol structures are purely syntactic

The symbols do not have any intrinsic meaning

Nor do the expressions built up out of them

The operations on physical symbols are sensitive only to the “shape” of those symbols

Formal rules, like the rules of a logical calculus

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

From syntax to semantics

One can specify a complete machine table for a TM without saying anything about what it is intended to represent (its intended interpretation)

The machine table just specifies what the appropriate transitions are for any possible combination of inputs and states

But if we assign meanings to the symbols then we can interpret the machine as carrying out specific calculations

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

A sample program

Q1 0 R Q2

Q1 1 0 Q1

Q2 0 1 Q3

Q2 1 R Q2

• The symbol “R” has a fixed meaning, since it is the instruction to move one square to the right

• But “0” and “1” do not mean anything

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

Running the program

Q1 0 1 1 0 1 1 0

Q1 0 0 1 0 1 1 0

Q2 0 0 1 0 1 1 0

Q3 0 0 1 1 1 1 0

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

An interpretation function

• An interpretation function gives a semantics

• assigns objects to symbols

“1”  1

“0”  punctuation mark

• makes it possible to interpret the TM as computing the function of addition

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

Syntax tracking semantics

Syntax:

“n” = a string of n “1”s bounded by “0”s

“m” = a string of m “1”s bounded by “0”s

“n + m” = a string of n + m “1”s bounded by “0”s

Semantics:

“n” designates n

“m” designates m

Isomorphism

Given inputs “n” and “m” the TM outputs “n +m” just when “n + m” designates the sum of n + m

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

Background to the Russian room

The Russian room argument exploits an intuitive contrast between

The way that the outputs of a computer result from operations on strings of symbols (“1”s and “0”s)

The way that human behavior results from rational thought involving propositional attitudes

Searle uses the CRA to argue that this contrast is fatal to the project of strong AI (idea that appropriately programmed computers might be minds)

PSSH is committed to strong AI

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

The Russian room

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

The main claims

The Russian Room is input-output identical to a real Russian speaker

The “internal processing” in the Russian room is purely syntactic (based on the shapes of the symbols)

The person in the Russian room has no understanding of Russian

Therefore, what is going on in someone who really does understand Russian (or anything else) cannot be the sort of processing that takes place in the Russian room

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

What is genuine understanding?

Clearly cannot be understood in purely behavioral terms

i.e. producing the appropriate outputs for given inputs

The CR passes the Turing Test

Searle: “Understanding a language, or indeed having mental states at all, involves more than just having a bunch of formal symbols. It involves having an interpretation or a meaning attached to those symbols” (In Chalmers, p. 671)

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

Possible responses

Reject the intuition that the CR does not understand Russian

Concede that the CR does not genuinely understand Russian, but find an alternative explanation of the lack of understanding that does not rule out strong AI

Concede that the Russian room does not genuinely understand Russian, but show how we might build up from the CR to a system that does understand Russian

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

Strategy 2: system reply

The thought experiment is set up so that the question of whether the CR understands Russian is equivalent to the question of whether the person in the CR understands Russian

But even if we agree that the the person in the room only has a “phrase book” understanding of Russian, this is perfectly compatible with the system as a whole having genuine linguistic understanding

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020

Strategy 3: robot reply

The input-output test is not a good criterion for genuine understanding

It is purely verbal

A much better test of linguistic understanding is whether the CR can interact with the world appropriately

• obey instructions and commands

• name and describe objects correctly

• initiate conversations in a relevant manner

Cognitive Science  José Luis Bermúdez / Cambridge University Press 2020