Lee,BerkeleyUniversityofCaliforniaatBerkeley

IntelligenceandComputationAModel-BasedDesignPerspective

EdwardA.Lee

Eindhoven,TheNetherlands,April9,2019

ESI Symposium

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WhatisaModel?

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Amodelisanydescriptionofasystemthatisnotthething-in-itself.(dasDingansichinKantianphilosophy).

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WhatisIntelligence?

TheTuringTestisallaboutimitatinghumanintelligence,notaboutbuildingintelligentsystems.

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ELIZA: Please tell me what's been bothering you.YOU: I think my computer is smarter than me.ELIZA: Do computers worry you?YOU: YesELIZA: You are sure.YOU: No, not really.ELIZA: Are you saying no just to be negative?

elizabothttp://www.masswerk.at/elizabot/

JosephWeizenbaumELIZA,1966

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IsELIZAIntelligent?

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“[O]nceaparticularprogramisunmasked,onceitsinnerworkingsareexplainedinlanguagesufficientlyplaintoinduceunderstanding,itsmagiccrumblesaway;itstandsrevealedasamerecollectionofprocedures,eachquitecomprehensible.Theobserversaystohimself`Icouldhavewrittenthat.’Withthatthoughthemovestheprograminquestionfromtheshelfmarked`intelligent,’tothatreservedforcurios,fittobediscussedonlywithpeoplelessenlightenedthanhe.”

[Weizenbaum,1966]

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ExplainingNaturalIntelligence

•  McCollochandPitts(1940s)•  Rosenblatt:Perceptrons(1950s)•  Putnam:multiplerealizability(1960s)•  Rumerlhart,Hinton,Williams:

neuralnets(1980s)•  Machinelearningexplosion(1910s)

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Mechanicalmanasenvisionedbyanunknownsixteenth-centuryItalianmaster,contemporaryof

LeonardodaVinci[WebGalleryofArt,PublicDomain]

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OversimplifyingNaturalIntelligence

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•  Neuronsfirediscretely.(McCullochandPitts,1940s)•  Neuronscombinetorealizelogicfunctions.•  Logicfunctionscanberealizedonotherhardware.(Putnam,1960s)

CamilloGolgi’smethod(1870s)givesamisleadingpictureofthebrain.

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TheBrainisMoreComplex

Canweunderstandbrainfunctionbystudyingthewiringdiagram,eveninprinciple?

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JeffLichtman,Harvard

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CrumbofMouseBrainReconstructedinFullDetail

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NatureNews,7/30/15,byAlisonAbbott

JeffLichtman,Harvard

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Wecan’texplainnaturalintelligence.Itturnsoutwecan’texplainartificialintelligenceeither.

DARPAXIAProgram:

9 DavidGunning,ProgramManager,XIA

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GoogleInception

10 MarcoTúlioRibeiro,SameerSingh,CarlosGuestrin(Univ.ofWashington,2016)

ElectricGuitar,AcousticGuitar,Labrador

ElectricGuitar AcousticGuitar Labrador

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RecognizingCarsandPedestrians

Self-drivingcarsneedtorecognizecarsandpedestrians.Doweunderstandhowhumansdothis?

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Howcanwebuildmodelsofsomethingwedonotunderstand

?

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ExplainableMechanicalSystems(XME)

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Inthisexample,themodelinguniverseiscalculusandNewton’slawsinatimeandspacecontinuum.

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Themodel

ImagebyDominiqueToussaint,GNUFreeDocumentationLicense,Version1.2orlater.

Thetarget

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DoWeUnderstandTime?

Weunderstandtime,right?

14 Aristotle

Change

Newton

Smooth

Einstein

Relative

Wheeler

Discrete

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DoWeUnderstandTime?

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Muller:Givesatheoryoftimethatrequiresbigblackholestocollidesomewherenearustotestit.

Rovelli:“Thenatureoftimeisperhapsthegreatestremainingmystery.”

2016 2018

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UnexplainableMechanicalSystems

Afewthingsweneedtomodeltoexplainthisbehavior:•  Plasticdeformation•  Acousticpropagation•  Stretchingofstrings•  Gravity•  …

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AnEpiphany

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TheValueofModels

•  Inscience,thevalueofamodelliesinhowwellitsbehaviormatchesthatofthephysicalsystem.

•  Inengineering,thevalueofthephysicalsystemliesinhowwellitsbehaviormatchesthatofthemodel.

Ascientistasks,“CanImakeamodelforthisthing?”Anengineerasks,“CanImakeathingforthismodel?”

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ModelFidelity

•  Toascientist,themodelisflawed.•  Toanengineer,therealizationisflawed.

I’manengineer…Perhapsweshouldbetryingtomakesystemsbehaveinmoreintelligentwaysratherthantryingtobuildsystemsthatemulatehumanintelligence.

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ConsiderChipDesign

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Apieceofsiliconthatdoesn’tbehavelikethemodelisjustbeachsand.

IntelHaswell,eachwith1.4billiontransistors

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UsefulModelsandUsefulThings

“Essentially,allmodelsarewrong,butsomeareuseful.”

Box,G.E.P.andN.R.Draper,1987:EmpiricalModel-BuildingandResponseSurfaces.WileySeriesinProbabilityandStatistics,Wiley.

“Essentially,allsystemimplementationsarewrong,butsomeareuseful.”

LeeandSirjani,“Whatgoodaremodels,”FACS2018.

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TheValueofSimulation

“Simulationisdoomedtosucceed.”Couldthisstatementbeconfusingengineeringandscientificmodels?

22 [Freemont,etal.,Scenic:Language-BasedSceneGeneration,Arxiv.org,Sept.2018]

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Howcanwebuildmodelsofsomethingwedonotunderstand

?Dowewantscientificmodelsorengineeringmodels?

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ChangingtheQuestion

Isthequestionwhetherwecanbuildmodelsthatbehavelikenaturalintelligentsystems?OrIsthequestionwhetherwecanbuildsystemsthatbehavelikeintelligentmodels?

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MoreIntelligentSystemsMayNotResembleHumansatAll

Selfawareness:Considerathermostat,miswiredsothattheheatcontrolisconnectedtotheACandviceversa.Whichonewillbemoreintelligent?

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ScientificModel-BasedDesignofIntelligentSystems

•  Modelthehumanbrain•  Buildsystemsbasedonthosemodels

Ifwearesuccessful,theneverymorning,Iwillhavetoarguewithmysmartcaraboutthevalueofgettingtoworkontime…

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DoesitReallyMatterWhetherItisAGorilla?

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AStory

Shouldpatientswithpneumoniabeadmittedtothehospitalortreatedathome?

Foundthatonatrainingdataset,patientswithariskofasthmahadalowerriskofdyingfrompneumoniathanthegeneralpopulation.

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RichCaruanaMicrosoftResearch

Caruana,etal.,2015:Intelligiblemodelsforhealthcare:Predictingpneumoniariskandhospital30-dayreadmission.InACMSIGKDDConferenceonKnowledgeDiscoveryandDataMining(KDD)

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WeMayNotYetHaveInventedtheTechnologytoReplicateHumanIntelligence

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HAL,thecomputerinStanleyKubrick’s1968movie,2001:ASpaceOdyssey

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FreeingtheMindFromMatter

•  Arewealone?•  Teleportation?•  Thesingularity?•  Uploading?

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TeleportationandUploading

Whathappensto“I”?•  Isthereconstructionthesame“I”?–  Howcanwetell?

•  Whatiftheoriginalisnotdestroyed?–  Two“I”s?

•  Whatifabackupcopyislaterinstantiated?–  Two“I”sofdifferentages?

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TheSenseofSelfPerThreePhilosophers

Whathappensto“I”?•  DerekParfit:–  Thenotionof“I”makesnosense.

•  DanielDennett:–  “I”isafiction,anillusion,asocialconstruction.

•  DouglasHoftstadter–  “I”canbeintwoplacesatonce.

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ASimplerAnswer:“I”IsNotDigital

33 ClaudeShannon

Shannonshowedin1948anoisychannelcan,inprinciple,perfectlyconveyafinitenumberofbits(the“channelcapacity”).Theconverseisevenmoreimportant:Anoisychannelcannotconveymorethanafinitenumberofbits.

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DigitalandComputationalMachines

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Turingmachine:Anabstractmachinethat,givenafinitedigitalinput,eithercomputesafinitedigitaloutputorfailstohalt.

UniversalTuringmachine:ATuringmachinethatcanrealizeanyotherTuringmachine,givenadigitalrepresentationofthatmachine.

Physicalrealization(WikimediaFoundationservers)[PhotobyVictorGrigas/WikimediaFoundation,CCBY-SA3.0]

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AUniversalTuringMachineisNotaUniversalMachine

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Amachinethatis(probably)notmodeledinanyusefulwaybyaTuringmachine.Itisneitherdigitalnoralgorithmic.

ByPiotrus,CCBY-SA3.0,viaWikimediaCommons

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HowManyMachines?

Myquestion:Ofallmachinesrealizableinthephysicalworld,howmanyareusefullymodeledasdigitalandalgorithmicmachines?

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CantorandCardinality

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Thesmallestofallinfinitesetsarethecountablesets.Elementsofacountablesetcanbeputintoaone-to-onecorrespondencewiththenaturalnumbers:0,1,2,3,4,…

GeorgCantor(1845-1918)

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TheSetofTuringMachinesisCountable

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ByWvbaileyCCBY-SA3.0 UncountablesetE.g.setofallODEs

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Countablesubset

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TheDNAFallacy

39 ByZephyris-Ownwork,CCBY-SA3.0

Naïveassumption:DNAencodestheinformationneededtocreateahuman(andhence,amind).Everyhumanalivetodayistheendpointofacontinuous,unbroken,biologicalprocessdatingbackaboutfourbillionyears.

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The“UniversalMachine”Fallacy

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Naïveassumption:Turingmachinesareuniversalmachines.Theyare:•  Algorithmic•  Digital•  Non-interactive•  Terminating

MachinedesignedbyMikeDaveyByGabrielF-Ownwork,CCBY-SA3.0

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WhatAretheOdds?

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Ishumanintelligencedigitalandcomputational?Weneedevidence…

Processesinnature

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Digital/computationalprocesses

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IsTheHumanMindDigitalandComputational?

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Manyaspectsarediscrete:•  Language•  Logic•  MathematicsEvidencethatitisnot:•  Consciousnessisnotexternallyobservable.•  Languageimperfectlyencodesourthoughts.•  Mosttruthsinourheadsnevergetexpressed.•  Communicatedideasareneverperfect.

AllsubjecttotheShannonChannelCapacityTheorem.

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PossibleMechanismsintheBrainthatareBeyondDigital/Computational

•  Timing•  Interaction•  Chaos(inducedbyfeedbackloops)•  Nondeterminism•  Chemistry•  Embodiment

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MostChaosisBeyondComputable

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Naïveassumption:Ifwecanwritedowntheequation,itmustbecomputable.

EdwardLorenz

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Determinism

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Naïveassumption:Newtonianmechanicsisdeterministic.

Pierre-SimonLaplace

MetastablesystemthatobeysallofNewton’slawsbutisnondeterministic.

Norton,J.D.(2007).CausationasFolkScience.InCausation,Physics,andtheConstitutionofRealityOxford,ClarendonPress:

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LessonsfromPsychology:EmbodiedCognition

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“Themindsimplydoesnotexistassomethingdecoupledfromthebodyandtheenvironmentinwhichitresides.”[Thelen,E.,2000:Groundedintheworld]

Human-likeAIwillmorelikelyarisefromcyber-physicalpystemsandcyber-humansystems,notcyberones.

EstherThelen(1941—2004)Developmentalpsychologist,

IndianaUniversity,pioneerofembodiedcognition.

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Conclusions

Wecan(anddo)buildmodelsofthingswedon’tunderstand.Thepertinentquestionisnotwhetherourmodelsaccuratelyreflectintelligenceinhumans,butratherwhetherwecanbuildphysicalartifactsthatbehavelikeintelligentmodels.

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MITPress,2017