By parallel reasoning: the construction and evaluation of analogical arguments

371 Pages·2010·1.409 MB·English

by  Bartha, Paul F. A

By Parallel Reasoning
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By Parallel
Reasoning
The Construction and Evaluation
of Analogical Arguments
. .
PAUL F A BARTHA
1
2010
3
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Bartha,PaulF.A.
Byparallelreasoning:theconstructionandevaluationof
analogicalarguments/PaulF.A.Bartha.
p. cm.
Includesbibliographicalreferencesandindex.
ISBN 978-0-19-532553-9
1. Analogy. 2.Reasoning. I.Title.
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Acknowledgments
Thisbookhastakenshapeovermanyyears,duringthecourseof
whichmanypeoplehavemadesignificantcontributions.JeffHorty,
AndrewIrvine,andJamesKelleherreadtheentireworkandoffered
manyvaluablesuggestions.Othercolleaguesandgraduatestudents
haveprovidedinsightfulcommentsandcriticismorpointedmeto
interestingexamples:JohnBeatty,DarrenBradley,RogerClarke,
EmmaEsmaili,ChrisHitchcock,RichardJohns,SoniaMemetea,
MargaretSchabas,andSteveSavitt.IwouldliketothankKeithHolyoak
forencouragementandsomeexcellentsuggestionsrelatingto
chapters4and8,andMikeRivers-Bowermanforusefulcriticismof
chapter6.IdeeplyappreciatetheencouragementoftheeditoratOxford
UniversityPressandtheterrificsuggestionsoftwoanonymous
reviewers;thosesuggestionssignificantlyimprovedthebook.Iowea
specialdebtofgratitudetoKevinAshley,NuelBelnap,BruceBuchanan,
RichardGale,KenManders,andaboveall,WesleySalmonfor
inspiringandguidingtheoriginaldissertationprojectfromwhich
thisbookemerged.Finally,mydeepestandeverlastinggratitude,for
unwaveringpatience,support,andencouragement,goestomy
parents,PeterandJeannie,andtomywife,Patricia.
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Preface
In1966,MaryHessepublishedModelsandAnalogiesinScience.Inaset
offiveessays,sheraisedfundamentalquestionsabouttheimportance
ofanalogiesinscientificthought.Areanalogiesneededto
understandtheoreticalconcepts,andaretheyindispensableto
theadvancementofscience?Whatcriteriaseparategoodanalogical
argumentsfrombadones?Whatphilosophicaljustificationcanbe
providedforreasoningbyanalogy?WhatdoesAristotlehavetotell
usabouttheroleofanalogiesinpredication?Isthereaconnection
betweenmetaphorandscientificexplanation?Inofferinganswersto
thesequestions,Hesseadvancedourunderstandingoftwoaspects
ofthetraditional“problemofanalogy”:theinferentialaspect,which
concernsanalogicalarguments;andthesemanticaspect,whichhas
todowiththeroleofanalogy(andmetaphor)inthedevelopmentof
concepts.Previousthinkershadconsideredbothissues,butHesse
wasthefirsttoworkoutdetailedargumentsthattheywerelinked.
During the past twenty-five years or so, research on analogy
hasbeentransformedbytheeffortsandinterestsofAIresearchers,
psychologists,andcognitivescientists.Therearenowalargenumberof
computationaltheoriesofanalogy,implementedincomputerprograms
thatperformanalogicalreasoningandrelatedtasks.Theintroduction
toTheAnalogicalMind,arecentanthologyof“state-of-the-art”essays
(Gentner,Holyoak,andKokinov2001),givesagoodideaofhow
cognitivescientistsnowunderstandthecentralissuesconcerning
analogy.Theseissuesarestructuredaroundawidelyaccepteddecom-
positionofthe“processofanalogicalthinking”intofoursteps:1
1. SeealsoHolyoakandThagard(1989),whichlaysoutasimilardecomposition.
viii PREFACE
• Retrievaloraccessofarelevant“source”analog
• Mappingthatsetsupsystematiccorrespondencesbetweentheelementsof
thesourceand“target”analogs
• Analogicalinferenceortransferofinformationfromsourcetotarget
• Learningofnewcategoriesorschemasintheaftermathofanalogical
reasoning
Many researchers hope to offer a psychologically realistic model of one or
moreofthesestagesthatis,atleastinprinciple,capableofbeingtranslatedintoa
computerprogram.Thelargerobjectiveistounderstandwhatpeopledoateach
ofthesestageswhentheyuseanalogiesandhowtheydoit.Subsidiaryobjectives
include the exploration of technical difficulties in implementing these ideas in
computer programs, the application of analogy to tasks besides reasoning and
problem-solving,andunderstandinghowanalogyisintegratedintolargerscale
cognitiveprocesses(Forbus2001).
Inshort,thepredominantconcernincurrentresearchistomodelanalogyas
a cognitive process. This has led to a climate in which there is little room for
Hesse’s second and third questions—those concerned with the nature and
justification of analogical reasoning. While there are now many models of
analogicalreasoning,therearefewmodelsforthecriticalevaluationofanalogi-
calreasoning.Tobesure,cognitivescientistsstresstheneedforevaluationatthe
analogical transfer stage, but that often amounts to checking that the models
produceplausibilityjudgmentsthatarepsychologicallyrealistic.Thelegitimacy
oftheseplausibilityjudgmentsisnotquestionedfurther.
Yetwe surely need tothinkabout Hesse’squestions.Substantivecomputa-
tional models of analogical reasoning obviously embody normative principles,
and those principles should be subjected to criticism.2 A computer program
mightbeeerilysuccessful induplicatinghumanreasoning, yetproduceflawed
analogicalarguments—justashumansdo.Oritmightproduceexcellentresults,
in which case we would want to understand the underlying ideas and their
philosophicalbasis.Bywayofcomparison,supposethatwewanttounderstand
the psychological processes people employ to come up with mathematical
proofs. We write a computer program that breaks these processes into stages
andduplicateshumanreasoningateachstage.Thatisasignificantaccomplish-
ment. But we still demand a logic that discriminates between good proofs and
badones.Somehow,whenweturntotheliteratureonanalogicalreasoning,we
find that this demand has all but disappeared. That is surprising, in light of
empirical evidence that shows how easily people can be misled by analogical
arguments.3
Onereasonforthefadingurgencyofthetraditionalquestionsisthegrowing
conviction that much of what takes place under the heading “analogical
2. Chapter3examinesaselectionofcomputationalmodels,withaviewtoisolatingandevaluatingthetacit
normativetheories.Inparticular,thatchapterexaminestheprincipleofsystematicityemployedbymostcurrent
computationalmodels.
3. SeeForbus,Gentner,andLaw(1995)andGickandHolyoak(1980,1983)forevidencethatpeopleregularly
focusonsuperficialsimilaritieswhenevaluatinganalogies.
PREFACE ix
reasoning” is not really inference but rather something akin to perception. The
Analogical Mind (Gentner, Holyoak, and Kokinov 2001) includes essays on
analogicalthinkinginyoungchildrenandnonhumanprimates.Inanepilogue
tothebook,Hofstadterwritesthatreasoningandproblem-solvinglie“farindeed
fromthecoreofhumanthought,”andcomments:
Ifanalogyweremerelyaspecialvarietyofsomething[reasoning]thatin
itselflieswayoutontheperipheries,thenitwouldbebutanitty-bitty
blipinthebroadblueskyofcognition.Tome,however,analogyis
anythingbutabittyblip—rather,it’stheverybluethatfillsthewholesky
ofcognition—analogyiseverything,orverynearlyso,inmyview.
(Gentner,Holyoak,andKokinov2001,499)
Thesesentiments,andthemorespecificthesisthatanalogy-makingisaprocess
much like perception, are defended in Hofstadter’s (1995) book, Fluid Concepts
and Creative Analogies. While I am sympathetic to much of what he says, I
nevertheless believe in the importance of distinguishing between the process
ofrecognizingorcreatingananalogyanditscriticalassessment.
Analogies play a vast and mysterious part in human thought. We rely on
them when we identify complex patterns, bring past experience to bear on a
problem, or strive to attain a perspective that unifies different areas of inquiry.
Thereareplentyofbigquestions,manyofthemopenedupbyrecentresearch.
Howdohumansconstructanalogies?Dononhumananimalsuseanalogiesina
similar way to humans? What role does analogy have in defining and under-
standingconcepts?Whatistherelationshipbetweenanalogiesandmetaphors?
What prospect do computational models of analogy have for illuminating how
humansreason(oroughttoreason)byanalogy?Aretheanalogiesemployedin
scientificreasoningdifferentfromthosewefindinotherkindsofinquiry?
In this book, I focus on a single thesis: good analogical arguments are an
important means of establishing the plausibility of scientific hypotheses. I
concentrate on two questions: (1) what criteria should we use to evaluate the
analogicalargumentsusedinscience,and(2)howcanweprovideaphilosophical
justification for those criteria? These questions relate to only one stage in the
reasoning process and aredirectedtoward thespecializedanalogiesthat wefind
inscience.
Yetcanwereallyhopetoanswersuchquestionsinisolationfromabroader
theory of analogy-making? The theory of conceptual metaphor, presented in
George Lakoff and Mark Johnson’s Metaphors We Live By (1980), suggests a
negative answer. According to the theory of conceptual metaphor, the source
domain in any metaphor (or analogy) must always be some element of “direct
physical experience” that can be grasped nonmetaphorically because it comes
from our everyday activities as embodied human beings living in a particular
culture. Typical examples include journeys (“Life is a journey”), spatial orienta-
tion(“He’satthepeakofhiscareer”),andwar(“Heattackedeveryweakpointin
myargument”).InarecentapplicationofLakoffandJohnson’stheorytometa-
phorsinscience,TheodoreBrown(2003)embracestheirviewthatallmetaphors