Computational logic and human thinking : how to be artificially intelligent

333 Pages·2011·3.84 MB·English

by  Robert Kowalski

ComputationalLogicandHumanThinking
HowtobeArtificiallyIntelligent
Thepracticalbenefitsofcomputationallogicneednotbelimitedtomathematicsand
computing.Asthisbookshows,ordinarypeopleintheireverydaylivescanprofitfrom
therecentadvancesthathavebeendevelopedforartificialintelligence.Thebookdraws
uponrelateddevelopmentsinvariousfieldsfromphilosophytopsychologyandlaw.It
paysspecialattentiontotheintegrationoflogicwithdecisiontheory,andtheuseoflogic
toimprovetheclarityandcoherenceofcommunicationinnaturallanguagessuchas
English.
Thisbookisessentialreadingforteachersandresearcherswhowanttocatchupwith
thelatestdevelopmentsincomputationallogic.Itwillalsobeusefulinany
undergraduatecoursethatteachespracticalthinking,problemsolvingorcommunication
skills.Itsinformalpresentationmakesthebookaccessibletoreadersfromany
background,butoptional,moreformal,chaptersarealsoincludedforthosewhoaremore
technicallyoriented.
robert kowalski isEmeritusProfessorandResearchInvestigatorinthe
DepartmentofComputingatImperialCollegeLondon.In2011hereceivedtheIJCAI
AwardforResearchExcellenceforhiscontributionstologicforknowledge
representationandproblemsolving,includinghispioneeringworkonautomated
theoremprovingandlogicprogramming.

Computational Logic
and Human Thinking
How to be Artificially Intelligent
ROBERT KOWALSKI
ImperialCollegeLondon
cambridge university press
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Singapore,SãoPaulo,Delhi,Tokyo,MexicoCity
CambridgeUniversityPress
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©R.Kowalski2011
Thispublicationisincopyright.Subjecttostatutoryexception
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noreproductionofanypartmaytakeplacewithoutthewritten
permissionofCambridgeUniversityPress.
Firstpublished2011
PrintedintheUnitedKingdomattheUniversityPress,Cambridge
AcataloguerecordforthispublicationisavailablefromtheBritishLibrary
LibraryofCongressCataloguinginPublicationdata
Kowalski,Robert.
Computationallogicandhumanthinking:howtobeartificially
intelligent/RobertKowalski.
p. cm.
ISBN978-0-521-19482-2(hardback)
1. Computationalintelligence. 2. Logic,Symbolicandmathematical–Famous
problems. 3. Rhetoric–Mathematics. 4. Communication–Philosophy.
5. Reasoning. 6. Criticalthinking. I. Title.
Q342.K69 2011
511.3–dc22
2011002461
ISBN978-0-521-19482-2Hardback
ISBN978-0-521-12336-5Paperback
CambridgeUniversityPresshasnoresponsibilityforthepersistenceor
accuracyofURLsforexternalorthird-partyinternetwebsitesreferredto
inthispublication,anddoesnotguaranteethatanycontentonsuch
websitesis,orwillremain,accurateorappropriate.
ToBob,JohnandMary

Contents
Preface pageix
Summaryandplanofthebook xii
Introduction 1
1 LogicontheUnderground 9
2 Thepsychologyoflogic 24
3 Thefoxandthecrow 40
4 Search 50
5 Negationasfailure 60
6 HowtobecomeaBritishCitizen 77
7 ThelouseandtheMarsexplorer 92
8 Maintenancegoalsasthedrivingforceoflife 107
9 Themeaningoflife 125
10 Abduction 134
11 ThePrisoner’sDilemma 144
12 Motivationsmatter 155
13 Thechangingworld 166
14 Logicandobjects 179
15 Biconditionals 188
16 ComputationalLogicandtheselectiontask 198
17 Meta-logic 213
Conclusionsofthebook 227
A1 Thesyntaxoflogicalform 231
A2 Truth 247
A3 Forwardandbackwardreasoning 257
vii
viii Contents
A4 Minimalmodelsandnegation 263
A5 Theresolutionrule 269
A6 Thelogicofabductivelogicprogramming 280
References 296
Index 303
Preface
ThemerepossibilityofArtificialIntelligence(AI)–ofmachinesthatcanthink
andactasintelligentlyashumans–cangeneratestrongemotions.Whilesome
enthusiastsareexcitedbythethoughtthatonedaymachinesmaybecomemore
intelligentthanpeople,manyofitscriticsviewsuchaprospectwithhorror.
Partlybecausethesecontroversiesattractsomuchattention,oneofthemost
importantaccomplishmentsofAIhasgonelargelyunnoticed:thefactthatmany
ofitsadvancescanalsobeuseddirectlybypeople,toimprovetheirownhuman
intelligence.ChiefamongtheseadvancesisComputationalLogic.
Computational Logic builds upon traditional logic, which was originally
developedtohelp people thinkmoreeffectively.Itemploysthetechniquesof
symbolic logic, which has been used to build the foundations of mathematics
and computing. However, compared with traditional logic, Computational
Logic is much more powerful; and compared with symbolic logic, it is much
simplerandmorepractical.
Although the applications of Computational Logic in AI require the use of
mathematicalnotation,itshumanapplicationsdonot.Asaconsequence,Ihave
writtenthemainpartofthisbookinformally,toreach aswideanaudienceas
possible. Because human thinking is also the subject of study in many other
fields,IhavedrawnuponrelatedstudiesinCognitivePsychology,Linguistics,
Philosophy,Law,ManagementScienceandEnglishComposition.
Infact,thevariantofComputationalLogicpresentedinthisbookbuildsnot
onlyupondevelopmentsoflogicinAI,butalsouponmanyothercomplementary
and competing knowledge representation and problem-solving paradigms. In
particular,itincorporatesproceduralrepresentationsofknowledgefromAIand
Computing, production systems from AI and Cognitive Science, and decision
analysisfromManagementScience,CognitivePsychologyandPhilosophy.
Because Computational Logic has so many applications and so many rela-
tions with other fields, the ideal, ultimate use of this book would be as a
ix