Thinking Computers Varol Akman Bilkent University Computer Engineering and Philosophy 6 April 2005 Boğaziçi University Cognitive Sciences Graduate Program.

Thinking ComputersThinking Computers

Varol AkmanVarol AkmanBilkent UniversityBilkent University

Computer Engineering and PhilosophyComputer Engineering and Philosophy

6 April 20056 April 2005

BoğaziçiBoğaziçi University UniversityCognitive Sciences Graduate ProgramCognitive Sciences Graduate Program

Donald Davidson (1917-2003)Donald Davidson (1917-2003)

Carried forward Carried forward the the (late) (late) WittgensteinWittgensteinian ian notion that social notion that social interaction and interaction and exchange exchange areare the the basis of knowledgebasis of knowledge

Challenged the Challenged the ((CartesianCartesian)) viewview that that an individual mind an individual mind could know about the could know about the worldworld all by itself all by itself

Tom Nagel on DavidsonTom Nagel on Davidson

DescartesDescartes We understand ourselves better than the rest of We understand ourselves better than the rest of

the world, and we have to construct the objective the world, and we have to construct the objective reality outside of ourselvesreality outside of ourselves

Davidson really tried to reverse that:Davidson really tried to reverse that: Understanding ourselves depends on Understanding ourselves depends on

understanding we are part of a real world in understanding we are part of a real world in communication with otherscommunication with others

Davidson’s conclusion Davidson’s conclusion

[An artifact, e.g., a computer] thinks only if its [An artifact, e.g., a computer] thinks only if its thinking can be understood by a human thinking can be understood by a human interpreter, and this is possible only if the interpreter, and this is possible only if the artifact physically resembles a person in artifact physically resembles a person in important ways, and has an appropriate important ways, and has an appropriate history.history.

- D. Davidson (1990): - D. Davidson (1990): Turing’s TestTuring’s Test

Turing’s Test (TT)Turing’s Test (TT)

Due to ADue to Alanlan Turing Turing (1950): (1950): Computing Computing Machinery and Machinery and IntelligenceIntelligence

A computer thinks if A computer thinks if it can consistently it can consistently beat a human beat a human opponent in aopponent in ann imitation gameimitation game

ShShifting attitudeifting attitude

An operational test (quacks like a duck & An operational test (quacks like a duck &

walks like a duck walks like a duck a duck!) a duck!) Can a computer think?Can a computer think?

(Turing believed the word ‘think’ cannot be (Turing believed the word ‘think’ cannot be meaningfully applied to machines)meaningfully applied to machines)

Under what circumstances would a computer Under what circumstances would a computer

be mistaken for a person?be mistaken for a person?

The imitation gameThe imitation game

Two contestants (one human, one computer): Two contestants (one human, one computer): H and CH and C

One judge (human): JOne judge (human): J H & C are hidden from J but can H & C are hidden from J but can

communicate with him by exchanging communicate with him by exchanging messagesmessages

J types out questions addressed to H & CJ types out questions addressed to H & C

The imitation game cont.The imitation game cont.

J is placed before two terminalsJ is placed before two terminals H tries to convince J that he is human, while H tries to convince J that he is human, while

C does likewise (tries to convince J that it is C does likewise (tries to convince J that it is human)human)

If the judge cannot regularly identify the If the judge cannot regularly identify the computer, the computer is declared a thinkercomputer, the computer is declared a thinker

RecapRecap

If J cannot tell the difference between the If J cannot tell the difference between the

conversation with the other person (H) and conversation with the other person (H) and

the conversation with the machine (C), then the conversation with the machine (C), then

C is thinkingC is thinking Note: no restriction on the topic of Note: no restriction on the topic of

conversation (all possible areas of human conversation (all possible areas of human concern)concern)

Recap cont.Recap cont.

The insight underlying TT is the same insight The insight underlying TT is the same insight that inspires the new practice among that inspires the new practice among symphony orchestras of conducting auditions symphony orchestras of conducting auditions with an opaque screen between the jury and with an opaque screen between the jury and the musician.the musician.

- D- Danan Dennett (1985) Dennett (1985)

Game formatGame format

Instructions to J:Instructions to J: One of these terminals is connected to a One of these terminals is connected to a

person, the other to a computerperson, the other to a computer You have You have tt minutes (e.g., 5, according to minutes (e.g., 5, according to

Turing) to chat with them through these Turing) to chat with them through these terminals and to determine which is whichterminals and to determine which is which

Causal connectionsCausal connections

J is ignorant of the physical traits of CJ is ignorant of the physical traits of C But J must know it is H & C that are But J must know it is H & C that are

physically responsible for the symbol physically responsible for the symbol sequences observed in the terminals (that sequences observed in the terminals (that is, they have the causal capacity to is, they have the causal capacity to produce these texts)produce these texts)

The Yogi Berra methodThe Yogi Berra method

You can observe a lot just by You can observe a lot just by watchwatchinging Is it a man or a woman?Is it a man or a woman? also by being told (if I can’t see it), etc.also by being told (if I can’t see it), etc.

I’m determining whether it thinks wI’m determining whether it thinks withoutithout inspecting what it thinksinspecting what it thinks

A sufficient conditionA sufficient condition

In TT, meaningful verbal responses are In TT, meaningful verbal responses are regarded as the ‘mark’ of thoughtregarded as the ‘mark’ of thought

Should language be a prerequisite for Should language be a prerequisite for mentality?mentality?

Maybe there are other sufficient criteria for Maybe there are other sufficient criteria for thought (but let’s put that aside in this talk)thought (but let’s put that aside in this talk)

The modified TTThe modified TT

Remove H from the experimental set-up (all Remove H from the experimental set-up (all kinds of hacks can be -- and to some extent, kinds of hacks can be -- and to some extent, have been -- designed to fool J for 5 minutes)have been -- designed to fool J for 5 minutes)

More importantly, regard C as a thinking thing More importantly, regard C as a thinking thing even if we can distinguish it from H without even if we can distinguish it from H without much effortmuch effort

Shifting goalShifting goal

How good is a computer in imitating the How good is a computer in imitating the verbal behavior of a person?verbal behavior of a person?

What are J’s criteria for the presence of What are J’s criteria for the presence of thought? In other words, is the object (O) thought? In other words, is the object (O) thinking?thinking?

‘‘Speaking’ EnglishSpeaking’ English

O produces answers in English in response O produces answers in English in response to J’s questions in Englishto J’s questions in English

But how can J make sure that O understands But how can J make sure that O understands English?English? Right syntaxRight syntax Relevant (Relevant (àà la Sperber & Wilson?) answers la Sperber & Wilson?) answers AutonomyAutonomy

Caveat Caveat rere syntax syntax

On my naming day when I come 12 I gone On my naming day when I come 12 I gone front spear and kilt a wyld boar he parbly ben front spear and kilt a wyld boar he parbly ben the last wyld pig on the Bunder Downs any the last wyld pig on the Bunder Downs any how there hadnt ben none for a long time how there hadnt ben none for a long time befor him nor I aint looking to see none agen.befor him nor I aint looking to see none agen.

- Russell Hoban, Russell Hoban, Riddley WalkerRiddley Walker

Caveat Caveat rere syntax cont. syntax cont. The fall The fall

(bababadalgharaghtakamminarronnkonnbronntonnerron(bababadalgharaghtakamminarronnkonnbronntonnerronntuonnthunntrovarrhounawnskawntoohoohoordenenthurntuonnthunntrovarrhounawnskawntoohoohoordenenthurnuk!) of a once wallstrait oldparr is retaled early in bed nuk!) of a once wallstrait oldparr is retaled early in bed and later on life down through all christian minstrelsy. and later on life down through all christian minstrelsy. The great fall of the offwall entailed at such short notice The great fall of the offwall entailed at such short notice the pftjschute of Finnegan, erse solid man, that the the pftjschute of Finnegan, erse solid man, that the humptyhillhead of humself prumptly sends an unquiring humptyhillhead of humself prumptly sends an unquiring one well to the west in quest of his tumptytumtoes: and one well to the west in quest of his tumptytumtoes: and their upturnpikepointandplace is at the knock out in the their upturnpikepointandplace is at the knock out in the park where oranges have been laid to rust upon the park where oranges have been laid to rust upon the green since devlinsfirst loved livvy.green since devlinsfirst loved livvy.

- James Joyce, - James Joyce, Finnegans WakeFinnegans Wake

Semantics of OSemantics of O

J has no idea J has no idea rere the semantics of O, i.e., the semantics of O, i.e., words that appear on J’s screen and words that appear on J’s screen and events/things in the worldevents/things in the world

Maybe the (apparent) semantics was Maybe the (apparent) semantics was provided by someone who had originally provided by someone who had originally programmed Oprogrammed O

In this case, O is not really thinking!In this case, O is not really thinking!

Semantics of O cont.Semantics of O cont.

To see whether O has any semantics, J must To see whether O has any semantics, J must study the connection between O’s sentences study the connection between O’s sentences and the world (W)and the world (W)

J would like to know how O’s responses are J would like to know how O’s responses are in agreement with events and things in the in agreement with events and things in the world known to Jworld known to J

In short, we need to locate intelligence yet In short, we need to locate intelligence yet the invisible computer poses problemsthe invisible computer poses problems

Naïve physicsNaïve physics

Formulate little thought experiments about Formulate little thought experiments about the physics of daily life (naïve physics)the physics of daily life (naïve physics)

J says to O:J says to O: You are given a shoestring and a children’s truck. You are given a shoestring and a children’s truck.

Can you pull the truck using the string? Can you Can you pull the truck using the string? Can you push it? Tell me howpush it? Tell me how

This way there is no need to observe O This way there is no need to observe O interact with the world; there is no need for a interact with the world; there is no need for a body eitherbody either

Watching OWatching O

Permit J to observe O interact with WPermit J to observe O interact with W

MAJOR CHANGE IN VIEW!MAJOR CHANGE IN VIEW!

3-way interaction between J, O, and a 3-way interaction between J, O, and a shared world W (consshared world W (consisting of isting of mutually mutually observed events, things, etc.)observed events, things, etc.)

The triangle is formed of the individual, all The triangle is formed of the individual, all other people, and the nonhuman universeother people, and the nonhuman universe

Are O’s physical characteristics crucial?Are O’s physical characteristics crucial?

Body mattersBody matters

O must be able respond to a large proportion O must be able respond to a large proportion of the world features that can be noted by Jof the world features that can be noted by J

It must be possible for J to notice (e.g., see) It must be possible for J to notice (e.g., see) that O is sensitive to those features of W and that O is sensitive to those features of W and that it is responding appropriatelythat it is responding appropriately

Weasley’s warningWeasley’s warning

Never trust anything that can think for itself if you Never trust anything that can think for itself if you can’t see where it keeps its brain.can’t see where it keeps its brain.

- J.K. Rowling- J.K. RowlingHarry Potter and the Chamber of SecretsHarry Potter and the Chamber of Secrets

IndistinguishabilityIndistinguishability

How much like a person O must be to have How much like a person O must be to have thoughts?thoughts?

This is probably not easily answerableThis is probably not easily answerable Maybe too much difference puts limits on the Maybe too much difference puts limits on the

possibility of communication (an elephant possibility of communication (an elephant vs.vs. an ant?)an ant?)

Indistinguishability cont.Indistinguishability cont.

Mobility, size, sense organsMobility, size, sense organs Displaying emotionsDisplaying emotions Surely, thoughtfulness is a matter of degree:Surely, thoughtfulness is a matter of degree:

NewbornNewborn

Developing childDeveloping child

AdultAdult

AugmentorsAugmentors

Any mismatch between J and O Any mismatch between J and O rere sensitivity sensitivity to the features of W can be resolved by O, if to the features of W can be resolved by O, if it is indeed cleverit is indeed clever

The obvious way for O to accomplish this is The obvious way for O to accomplish this is to use sensitivity augmentorsto use sensitivity augmentors A microscope is a sensitivity augmentorA microscope is a sensitivity augmentor A telescope is also a sensitivity augmentorA telescope is also a sensitivity augmentor

You get the ideaYou get the idea

Histoire d’OHistoire d’O

“… “… is a cat” & “… is a is a cat” & “… is a mat” are usually held as mat” are usually held as a result of experiences a result of experiences with real cats & mats with real cats & mats (how about “is a (how about “is a unicorn”?)unicorn”?)

The cats are on the matThe cats are on the mat That’s a catThat’s a cat That’s a matThat’s a mat

Histoire d’O cont.Histoire d’O cont.

Q: Where are the cats? Q: Where are the cats?

A: The cats are on the matA: The cats are on the mat

Reasonable assumption:Reasonable assumption: In the history of O, a knowledge of In the history of O, a knowledge of catscats, ,

matsmats, and the notion of , and the notion of being-on-somethingbeing-on-something played role played role

But does O mean anything with A?But does O mean anything with A?

Histoire d’O cont.Histoire d’O cont.

Just think:Just think: Can you remember the French Revolution?Can you remember the French Revolution? Do you know Robespierre?Do you know Robespierre?

(no matter how much you(no matter how much youhave learned about thesehave learned about these

in HIST 101)in HIST 101)

It is unclear just what is necessary (a history It is unclear just what is necessary (a history of causal interactions?)of causal interactions?)

Conclusion Conclusion (EMBODIMENT)(EMBODIMENT)

… … the importance to genuine understanding the importance to genuine understanding of a rich and intimate perceptual of a rich and intimate perceptual interconnection between an entity and its interconnection between an entity and its surrounding world -- the need for something surrounding world -- the need for something like eyes and ears -- and a similarly complex like eyes and ears -- and a similarly complex active engagement with elements in that active engagement with elements in that world -- the need for something like hands world -- the need for something like hands with which to do things in that world.with which to do things in that world.


ConclusionConclusion (HISTORY) (HISTORY)

… … only a biography of sorts, a history of only a biography of sorts, a history of actual projects, learning experiences, and actual projects, learning experiences, and other bouts with reality, could produce the other bouts with reality, could produce the sorts of complexities (both external, or sorts of complexities (both external, or behavioral, and internal) that are needed to behavioral, and internal) that are needed to ground a principled interpretation of an entity ground a principled interpretation of an entity as a thinking thing…as a thinking thing…


Pictures from MITPictures from MIT

Humanoid Robotics GroupHumanoid Robotics Group

http://www.ai.mit.edu/projects/http://www.ai.mit.edu/projects/humanoid-robotics-group/humanoid-robotics-group/

CocoCoco

Rodney Brooks (MIT)Rodney Brooks (MIT)

CogCog


GenghisGenghis


HannibalHannibal


KismetKismet


disgusteddisgusted

happyhappyinterestedinterested

sadsad

surprisedsurprised

Thinking Computers Varol Akman Bilkent University Computer Engineering and Philosophy 6 April 2005 Boğaziçi University Cognitive Sciences Graduate Program.

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Thinking Computers Varol Akman Bilkent University Computer Engineering and Philosophy 6 April 2005 Boğaziçi University Cognitive Sciences Graduate Program.