Risk Harm and Responsibility

Risk, Harm, and Responsibility

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ThePhilosophicalFoundationsofTortLawDavidG.Owen

Printpublicationdate:1997PrintISBN-13:9780198265795PublishedtoOxfordScholarshipOnline:March2012DOI:10.1093/acprof:oso/9780198265795.001.0001

Risk,Harm,andResponsibilityStephenR.Perry

DOI:10.1093/acprof:oso/9780198265795.003.0015

AbstractandKeywords

Sinceriskisoneofthecentralconceptsinmoderntortlaw,anytheoryoftortsrootedinnotionsofinterpersonaljusticeandindividualresponsibilitymustgettogripswiththequestionspresentedinthischapter.Withaviewtocontributingtoaresponsibility-basedtheoryoftortlaw,thistheoryadvancesanddefendsthosequestions.Itoffersageneralanalysisofriskthatdrawsonworkinthephilosophyofprobabilityandsuggeststhattherearetwomainconceptionsofrisk.Thechapteralsoconsidersthethesisthatsubjectinganotherpersontoriskisaformofharmdistinctfromanyphysicalharmthepersonmightsuffer.Thisthesisismostplausibleifitisunderstoodaspresupposingtheobjectiveconceptionofrisk.Evenunderstoodinthatway,however,thethesiscannotbeaccepted;riskdoesnot,itargues,constituteharminitself.Thechapterthenconsidersmoralresponsibilityforphysicaldamage.

Keywords:risk,tortlaw,justice,responsibility,philosophy,probability,harm


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Whatisrisk?Doessubjectinganotherpersontoriskorreducinghisorherchanceofavoidinganadversephysicaloutcomeconstituteadistinctformofharm?Whatisthebasisofmoralresponsibilityforphysicalharmthatwasunintentionallycausedbyriskyconduct?Becauseriskisoneofthecentralconceptsinmoderntortlaw,anytheoryoftortsrootedinnotionsofinterpersonaljusticeandindividualresponsibilitymustcometogripswiththefirstandthirdofthesequestions.Inthelightofarecentacademicandjudicialtrendtocharacterizeriskasharm,aresponsetothesecondquestionshouldbeofinterestaswell.Inthisessay,withaviewtocontributingtoaresponsibility-basedtheoryoftortlaw,Iadvanceanddefendanswerstoallthreequestions.

InsectionI,Iofferageneralanalysisofriskthatdrawsonworkinthephilosophyofprobability.Isuggestthattherearetwomainconceptionsofrisk,oneobjectiveincharacterandtheotherepistemic,andthatbothare,indifferentways,plausiblecandidatesforexplainingthemoralsignificancethatweattributetorisk.InsectionII,Iconsiderthethesisthatsubjectinganotherpersontoriskisaformofharmdistinctfromanyphysicalharmthepersonmightsuffer.Thisthesisismostplausibleifitisunderstoodaspresupposingtheobjectiveconceptionofrisk.Evenunderstoodinthatway,however,thethesiscannotbeaccepted;riskdoesnot,Iargue,constituteharminitself.

InsectionIII,Iconsidermoralresponsibilityforphysicaldamage:underwhatcircumstancesshouldanagentwhoseriskyconductcausedunintentionalphysicalharmtoanotherpersonbeheldmorallyresponsibleforthatharm?Onecommonargument,whichIcallthelibertarianargument,suggeststhatpersonsshouldbeheldmorallyresponsibleforthematerializationofanyobjectiveriskthattheirconductcreates.Thelibertarianargumentwouldsupportastandardofabsoluteliabilityintortlaw,thusrequiringthatliabilitybeimposedsimplyforcausingharm.Boththeargumentandthestandardofabsoluteliabilitymust,however,berejected.Moralresponsibilityforphysicalharmshouldbegroundedinanotionofepistemicratherthanobjectiverisk.Thisunderstandingofresponsibility,which,borrowingatermfromTonyHonor,1calloutcome-responsibility,(p.322) isconsistentbothwiththenegligencestandardandwithrisk-basedstandardsofstrictliabilitysuchastheruleforultrahazardousactivities.

I.TheNatureofRiskFirst,whatisarisk?Inordinarylanguageconductistypicallysaidtoberiskywhenitgivesrisetoachanceofabadoutcomeofsomekind.Theconceptthusinvolvestwomainelements:first,anotionofchanceorprobability,andsecond,anotionofharm.Thepre-theoreticalconceptofriskpresumablydoesnotdefinetherelationshipbetweenthesetwoelementsinapreciseway,butanaturalmoveistostipulatethatariskisthemathematicalexpectationofharm,i.e.,theproductoftheprobabilityofoccur-renceoftheharmandthemagnitudeoftheharmwereittooccur(PH).Forpresentpurposesthenotionofharmcanbetreatedasunproblematic.1Letmelooselydefineharmasasetbacktoaninterest,andaninterestasanaspectofpersonalwell-being.Wemayassumethatindependentmoralargumentswilldeterminewhichinterestsareofsufficientimportancetowarrantprotectionbythelawoftorts;theconceptofriskcanthenbeappliedtopotentialinterferenceswiththeintereststhoseargumentssingleout.Thetroublesome


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aspectoftheconceptofrisk,andtheonethatplaysthemoreintrinsicroleinshapingitsmeaning,isnotharmbuttheelementofprobability.Theideaofriskcanapplytomanydifferenttypesofharmorbadoutcome,butwhatwemeanbyriskisfundamentallydeterminedbytheunderstandingofprobabilitywetaketheconcepttopresuppose.

Philosophershavedevelopedseveralquitedifferenttheoreticalaccountsofprobability.2Thesetheoriesaresometimestreatedascompetingandmutuallyincompatible,butthepredominantcontemporaryviewtendstoregardprobabilityinapluralistlight.Moreparticularly,ithasbecomecommonplacetorecognizethattwodistinctbutnon-conflictingconceptionsofprobabilitymustbothberecognized:oneisconcernedwithprob-abilitiesthatinsomewayhaveobjectiveexistence,whiletheothercharacterizesprobabilitiesintermsofthecurrentstateofourknowledgeandbeliefs.3Ishallcallthesetheobjectiveandepistemicconceptions,respectively.IanHackinghaswrittenthattheconceptofprobabilityhaspossessedthisessentialdualityeversinceitbegantoemergeinitsmodern(p.323) formintheseventeenthcentury.4Boththeobjectiveandtheepistemicconceptionsofprobabilitycanbegivenanumberofdifferentinterpretations.Toexplainwhattheseare,andtoshowwhyparticularinterpretationsareparticularlyappositeforunderstandingthemoralsignificanceofrisk,itwillbenecessarytotakeashortdetourthroughthebywaysofthephilosophyofprobability.

Tobeginwiththeobjectiveconception,peoplewhospeakofprobabilityinanobjectivesenseusuallyhaveinmindoneortheotheroftwoideas.Thefirstistheunderstandingofprobabilitythatemergesfromtheso-calledrelative-frequencytheoryofprobability.5Aprobabilityis,onthisview,justthestablerelativefrequencythatmaybeexhibitedbytheoccurrencesofagivenattributewithinaseriesofeventsorobjectsinthephysicalworld,wherethoseeventsorobjectscaninanappropriatewaybecharacterizedassimilar(e.g.,therelative-frequencyof.5associatedwiththeattributeofcomingupheadsinaseriesofsimilarevents,namely,theflipsofafaircoin).Theformaldefinitionofaprobabilityisusuallygivenasthelimitofafrequencywithinaninfinitesequence.Despitethisrelianceonthenotionofinfinity,therelative-frequencytheoryregardsprobabilitiesasjustacertainkindofempiricalfact.Thesecondideapeopletendtohaveinmindwhentheyspeakofobjectiveprobabilityisconcernedwiththeoperationofindeterministiccausalprocesses,suchasthoseassociatedwithquantummechanics.Ifaparticularoutcome,suchasthefinalrestingplaceofabilliardball,iscompletelydeterminedbytheprecedingstateofthephysicaluniverse,thentherelevantcausalprocessisdeterministic.Ifaparticularoutcome,saythetimeatwhichagivenuraniumatomdecays,isnotsodetermined,thenthecausalprocessisindeterministic.Thereisnofurther,perhapsunknown,causalmechanismthatliesbehindastatementoftheprobabilityofdecay.Onthisviewaprobabilityisagainacertainkindofempiricalfact,butonethathastodowiththenatureofcausalprocesses.

Thesetwosensesofobjectiveprobabilityarerelated.Toseetheconnection,firstrecallthataprobabilityintherelative-frequencysenseisdefinedwithrespecttoacertainreferenceclassofactualorpossibleevents.Theprobabilitythatagivencoinwillcomeupheads,forexample,isdefinedrelativetothereferenceclassofflipsofthatcoin.The


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causalprocessesunderlyingtheeventsinthereferenceclasscould,however,beeitherdeterministicorindeterministic.Assumethattherelativefrequencywithwhichagivencoincomesupheadsis.5.Ifthecausalprocessesinvolvedaredeterministic,thenitwillinprinciplebepossibletopredictwhetheragivencoin-flipwillcomeupheadsortails,andhencetopartitionthereferenceclassinadvanceintotwosub-classes,oneconsistingofallhead-eventsandthe(p.324) otherofalltail-events.Sofarasthefirstsub-classisconcerned,theprobabilityofthecoincomingupheadsisone,whereasforthesecondsub-classtheprobabilityiszero.If,ontheotherhand,thecausalprocessesareinde-terministic,thenitwillnotbepossibletopartitionthereferenceclassinthisway.Inanimportantsensetheprobabilitystatementexpressesanultimatefactabouttheuniverse.Butwhicheverofthesepossibilitiesholds,wecanstillmeaningfullyspeakoftherelativefrequency,withrespecttotheoriginalreferenceclassofallflipsofthecoin,ofitscomingupheads.Independentlyofwhethertherelevantcausalprocessesaredeterministicorindeterministic,therelativefrequencyof.5withwhichthecoincomesupheadsisanobjectivepropertyofthephysicalworld.Objectiveprobabilityintheindeterministicsenseisthusaspecialcaseofobjectiveprobabilityintherelative-frequencysense.

Ofcourse,theothersideofthiscoin(sotospeak)istheinterestingobservationthatobjectiveprobabilitycanexistinadeterministicuniverse;probabilityneednotbeviewedasmerelyanepistemicphenomenonthatemergesonlybecausewecanneverhavecompleteknowledgeofdeterministicprocesses.Eveniftheprecedingstateoftheuniversedeterminestheoutcomeofanygivencoinflip,thestatementthatthereisaprobabilityof.5thatthecoinwillcomeupheadsexpressesafactaboutthephysicalworld.Asapracticalmatter,ofcourse,wecannotpredictwhetheracoinwillcomeupheadsortails.Theresultofanygivencoinflipcanthusbecharacterizedasrandom,andthisissowhethertheunderlyingcausalprocessesaredeterministicorindeterministic.Thedistinctionbetweendeterminismandindeterminismturnsonpredictabilityinprinciple,notpredictabilityinpractice.Inpractice,notonlymightwebeunabletopredictparticularoutcomes,wemightnotknowwhetheritwasinprincipleevenpossibletopredictoutcomes,i.e.,wemightnotknowwhetherthecausalprocesseswereorwerenotdeterministic.Andevenifweknewthatoutcomeswerepredictableinprinciple,thiswouldnotnecessarilybeparticularlyusefulorsignificantinformation.(Itwouldnot,forexample,haveanyeffectonthevariouspurposesforwhichweflipcoins.)Moreoverthedistinctionbetweenpredictabilityinprincipleandunpredictabilityisbynomeanscrystalclear.6Takentogether,thesepointssuggestthatweshouldtreatrelativefrequencyratherthanindeterminacyasthemostbasicunderstandingofobjectiveprobability.FromnowonIshallaccordinglyemploythetermobjectiveprobabilitytomeantherelative-frequencyconceptionofprobability.Referencewillbemadetothespecialcaseofindeterminacyasandwhennecessary.

(p.325) Epistemicprobability,likeobjectiveprobability,canalsobegivendifferentinterpretations.Forpurposesofthisessay,however,whichisprimarilyconcernedwithriskregardedasamoralphenomenon,IshallassumethatepistemicprobabilityisbestunderstoodintermsofwhatIshallcallthereasonablenessaccount.Thereasonablenessaccountisbasedonthefollowingtwoassumptions:first,thatobjectiveprobabilitiesinthe


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relative-frequencysenseexist;andsecondly,thathumanbeingspossessinter-subjectivelyvalidstandardsofinductivereasoningandrationalbeliefthatareatleastpragmaticallyjustifiedandthatpermitthemtodiscoverorestimatethoserelativefrequencies.Epistemicprobabilityinvolves,accordingtothereasonablenessaccount,arelationbetweenevidentiarypremises,ontheonehand,andaconclusionaboutthewaytheworldis,ontheother.Theevidencewillconsist,often,ofpartialobservationsofrelativefrequencywithinasequenceof(possible)objectsoreventsthatcannotbeobservedinitsentirety,butsometimesitwilltakeamoreindirectform.Theconclusionwillbeanestimateofrelativefrequencywithinthetotalsequence.7Epistemicprobabilityjudgmentsarethusestimatesofobjectiveprobabilitiesthatarebasedon,andrelativeto,agivenbodyofevidence.8

Accordingtothereasonablenessaccount,epistemicprobabilityjudgementsarecapableofexpressingknowledgeabouttheworld,althoughthatknowledgewilloftenperhapsalwaysbeimperfectorincomplete.Thestandardsofreasoningassumedtobeappropriateforjustifyingthesejudgementsarebasedonthemodesofprobabilisticandinductivereasoning,bothformalandinformal,thathumanbeingsactuallyemploy.Thereareanumberofwaysinwhichthesestandardsmightbecharacterized:onemight,forexample,formulatepreciseinductiveprinciplesthatoperateinconjunctionwithformalstatisticaltechniquesandtheprobabilitycalculus;oronemightseektodiscoveraninformedconsensusabouttheprobabilityofagiventypeofevent;oronemightlooktotheprobabilityjudgementsofareasonableorrepresentativeperson.Differentcharacterizationsmightbesuitedtodifferentpurposes.Thusaformalcharacterization,employingsophisticatedstatisticaltechniques,mightbeparticularlyappropriateforscientificinquiry,whereasaninformalcharacterization,basedontheintuitiveprobabilityjudgementsofareasonableperson,mightbemoresuitablefordeterminingmoralresponsibility.Acharacterizationalongthelatter(p.326) linesis,notcoincidentally,reminiscentoftheunderstandingofrisktobefoundintortlaw.

Idonotattemptinthischaptertoestablishthetruthofthetwoassumptionsonwhichthereasonablenessaccountreststheexistenceofobjectiveprobabilities,andtheavailabilityofinter-subjectivelyvalidmethodsforestimatingthembuttheymustbetakentobetrueifaconceptionofriskbasedonepistemicprobabilityistohavemoralsignificance.Thefirstassumptionensuresthatepistemicjudgementsofriskareconcernedwithrealpossibilitiesofharm,whilethesecondensuresthatthosepossibilitiesarecapableofbeingestimatedbymodesofreasoningthatboththepersonwhocreatesariskandthepersonwhoissubjectedtoitcanaccept.Ifthefirstassumptionwerenottruewecouldstillformulateanon-objectiveconceptionofprobability,butasthediscussionbelowofradicalsubjectivismillustrates,itseemsunlikelythatwewouldbeleftwithamorallysignificantconceptofrisk.If,ontheotherhand,thesecondassumptionwerenottrue,therewouldbenoformsofcommonreasoningaboutrisk,andlittleornoagreementaboutwhatrisksexistedandhowserioustheywere.Thiswouldmakeitdifficult,ifnotimpossible,toformulatecommonstandardsofconductrelatingtoriskybehavior(whateverthattermmightmeaninsuchaworld).


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Thereareotherpossibleinterpretationsofepistemicprobabilitybesidesthereasonablenessaccount.IntheremainderofthissectionIwouldlikebrieflytodescribethetwomostinfluentialoftheseinterpretations,andtoindicatewhytheyarenotcapableofexplainingorilluminatingthemoralsignificancethatriskholdsforhumanbeings.ReaderswhodonotwishtoexploreprobabilitytheoryanyfurthermaysafelytakeafasterbutlessscenicrouteandskiptosectionII.

Thefirstofthetwoalternativeinterpretationsofepistemicprobabilityissuggestedbyradicalversionsofthesubjectivist(orpersonalist,orBayesian)theoryofprobabilitythathasitsrootsintheworkofF.P.Ramsey.9Onthegeneralsubjectivistview,ajudgementofprobabilitymeasuresaparticularindividualsactualdegreeofbelieforconfidenceinagivenproposition.Themeasureofdegreeofbeliefisusuallyunderstoodbehav-ioristically,byreferencetotheoddsthattheindividualwouldbewillingtoacceptwithinacoherentseriesofbets.Coherenceisunderstoodasconformitytothestandardprobabilitycalculus.Radicalversionsofsubjectivism,whichgiverisetotheparticularinterpretationofepistemicprobabilitywithwhichwearenowconcerned,holdthatcoherenceistheonlyconstraintonrationalbelief.Radicalsubjectivistsmaintainthatwecanspeakmeaningfully(p.327) onlyofindividualassessmentsofprobability;thereis,theyassert,nosuchthingasprobabilityinanobjectivesense.10Thisviewthusplacesveryminimalrestrictionsonwhatwillcountasrationalbelief:probabilityjudgementscanpermissiblyvaryquitewidelyfrompersontoperson.

Thesecondalternativeinterpretationofepistemicprobability,whichinsomerespectsresemblesthereasonablenessaccount,isgroundedintheso-calledlogical-relation(orapriori)theoryofprobability.11Theessentialideaisthatprobabilityisalogicalrelationbetweenaconclusionorhypothesisaboutthewaythingsare,ontheonehand,andpremisesthatsetoutevidencerelevanttothathypothesis,ontheother.Probabilityistakentobeameasureofthedegreeofrationalbeliefin(orconfirmationof)thehypothesis.Therelationbetweenpremisesandconclusionisunderstoodaslogicalratherthanpsychologicalincharacter,andtothatextentistakentobeanobjectivematter.12Atthesametime,however,probabilitystatementsarealwaysrelativetogivenevidenceonly.Bytreatingprobabilitystatementsaslogicaltruths,thisviewplacesquitestringentrestrictionsonwhatwillcountasrationalbelief.

Neithertheradicalsubjectivistnorthelogical-relationunderstandingofepistemicprobabilityseemsabletoexplainwhyweattributethemoralsignificancetoriskthatwedo.Theradicalsubjectivistaccountassumesthereisnoobjectiveconceptionofprobabilitythatextendsbeyondtheweakconstraintsofthecoherencerequirement.Onthisviewthereisnogeneralinter-subjectivebasisfordistinguishingamongrisks,andhencenobasisforholdingsomeonemorallyresponsibleforriskcreation.IfIthinkthatyouaredoingsomethingthatposesahighriskofharm,whereasyouthinkthattheriskislowornon-existent,nodeterminativeargument(apartfromconsiderationsofcoherence)couldbebroughttobearbyeitherofustoshowthattheotherwaswrong.Riskthusunderstoodwouldlackmoralsignificance,becauseitwouldhavenosystematicandagreed-uponrelationtothephysicalworldinwhichconsequencesfollowfromactions.


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Riskwouldbeanindicationofthebettingoddsagivenpersonwouldbewillingtoacceptinanobjectivelyunpredictableworld,andnothingmore.Perhaps,onaradicalsubjectivistunderstandingofprobability,anindividualsassessmentoftheriskshisorheractionposesforothersmightberelevant(p.328) toaninquiryintowhetherheorshehadaculpablestateofmind.Butsinceinaradicallysubjectivistworldthenotionofactinginordertobringaboutaneffectmightwellhaveameaningverydifferentfromtheonewenowattributetoit,eventhisisfarfromclear.

Ofcourseradicalsubjectivistsrecognizethat,forvariousreasons,individualsprobabilityjudgementsoftenconverge,buttheyregardthisasareflectionofpsychologicalratherthanphysicalregularities.13Aconsistentandrigorouslydevelopedradicalsubjectivistunderstandingofprobabilitywouldinfactseemtohavenoroomforourordinaryconceptofphysicalcausality,sincethatconceptpresupposesregularitiesinthephysicalworld.Ofcoursenothinginthisdiscussionofradicalsubjectivismestablishesthatamongthepropertiesoftheworldareobjectiveprobabilitiesintherelative-frequencysense.Theclaimissimplythatunlesstherearesuchobjectiveprobabilities,andunlessourepistemicconceptionofprobabilityissystematicallyrelatedtothem,theepistemicconceptionwilllackmoralsignificance.14

Turningnowtothelogical-relationunderstandingofepistemicprobability,thereareatleasttworeasonswhyitislikelytoproveproblematicfromamoralpointofview.Thefirstconcernsthefactthat,onthisunderstanding,probabilityjudgementsarenotempiricallyverifiablestatements:theyareregarded,rather,asexpressinganapriori,logicalrelationamongpropositions.Asinthecaseoftheradicalsubjectivistaccount,butfordifferentreasons,thelogical-relationunderstandingdoesnotregardprobabilityjudgementsasattemptstoestimaterelativefrequenciesinthephysicalworld.Asbefore,itisdifficulttoattributemoralsignificancetoanaccountofepistemicprobabilitythatlacksthisfeature;logicaltruthcannot,byitself,haveanymoralimport.Variousattemptshavebeenmadebylogical-relationtheoriststoshowhowandwhyaprioriprobabilityjudgementscantellussomethingaboutthephysicalworld,butweneednotdecideherewhetheranyofthesehavesucceeded.Forpresentpurposesitsufficestopointoutthatifasystematiclinkbetweenapriorijudgementsandempiricallyverifiablerelativefrequenciescanbeestablished,itisthatlinkthatwillmatterinanaccountofthemoralsignificanceofriskandnotthejudgementssupposedlogicalbasis.Inotherwordsitdoesnotmatter,fromamoralperspective,whetherthesenseofepistemicprobabilityjudgementsmustultimatelybeexplainedbyreferencetoalogicalrelationamongpropositions;thereasonablenessaccount,whichresemblesthelogical-relation(p.329) theoryinregardingprobabilityasinvolvingarelationbetweenevidentiarypremisesandaconclusionaboutthewaytheworldis,cansimplyremainagnosticonthisquestion.Whatultimatelymatters,fromamoralpointofview,iswhetherprobabilityjudgementsaregenerallyable,underspecifiablecircumstances,toserveasreliableestimatesofrelativefrequenciesinthephysicalworld.

Thesecondreasonwhythelogical-relationunderstandingofepistemicprobabilityisunlikelytobeabletoaccountforthemoralsignificanceofriskisthatthelogicalrelations


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thetheorypositsdonotseemtobereadilyaccessibletohumanunderstanding.Carnap,forexample,proposedaverycomplex,language-dependentschemeofinductivelogicthatdoesnotseempracticallyapplicablebyordinaryhumanbeingsexcepttoverysimple(andhighlysimplified)problemsofprobability.Difficultpracticalandphilosophicalquestionsalsoariseinspecifyingtheformallanguageinwhichtheschemeofinductivelogicistobeformulated.Evenifwewereabletoassertwithsomeconfidencethatthereissomelogicalrelation,representingauniquelycorrectprobabilityjudgement,betweenagivenbodyofevidenceandagivenconclusionabouthowthingsmightbe,thisfactwouldbeoflittlemoralsignificanceifhumanbeingsdidnotgenerallyhavethecapacitytoreasonintherequisitemanner.15

Ihavearguedinthissectionthattheepistemicconceptionofprobability,understoodintermsofthereasonablenessaccount,canplausiblyberegardedasonepossiblepointofdepartureforexplainingwhyweattributemoralsignificancetoriskcreation.ButIhavenotclaimedthatitistheonlysuchpointofdeparture.Sincethereasonablenessaccountmakesessentialreferencetotheobjectiveconceptionofrisk,itisplausibletothinkthatthelatterismorallysignificantinitsownright.Perhapsitistheonlymorallysignificantconceptionofrisk,andlendstheepistemicconceptionwhateverplausibilityithasinthisregardbymeansoftheconceptuallinkbetweenthem.Thusindiscussingwhetherriskisadistinctformofharm,andinexaminingthebasisofmoralresponsibilityforphysicalharmcausedbyriskyconduct,itisimportanttoensurethatneitherobjectivenorepistemicprobabilityisoverlooked.Asweshallsee,thethesisthatriskisadistinctformofharmisbestunderstoodintermsofobjectiverisk,whereasmoralresponsibilityforphysicalharmshouldbeunderstoodasbeingbasedonepistemicrisk.

(p.330) II.IsRiskaHarminItself?Anumberofwritersandjudgeshavesuggestedinrecentyearsthatsubjectinganotherpersontoariskofphysicalharm,or,alternatively,reducinghisorherchanceofavoidinganadversephysicaloutcome,isitselfaformofharmthatshouldbecompensableintortlaw.16Itwillbeconvenienttodiscussthisissuewithreferencetoaconcretesetoffacts.TheEnglishcaseofHotsonv.EastBerkshireAreaHealthAuthority,17inwhichaclaimforlostchancewasputforward,isquitesuitableforthispurpose.

ThefactsinHotsonwereasfollows.Theplaintiffsufferedafractureofhisleftfemoralepiphysis,whichthedefendanthealthauthoritynegligentlyfailedtodiagnose.Althoughtheinjurywascorrectlydiagnosedandtreatedfivedayslater,theplaintiffeventuallydevelopedaseriouslydisablingconditionknownasavascularnecrosis.Theimmediatecauseofthisconditionwasareductioninthesupplyofbloodreachingtheepiphysis.Thisreductioncouldhavebeencausedeitherbytheruptureatthetimeofthefractureofasufficientlyhighproportionofthebloodvesselssupplyingtheepiphysis,orbysubsequentocclusionbypressurewithinthejointduringthefive-dayperiodbeforepropertreatmentwasadministered.Thetrialjudgefoundasafactthatatthetimetheplaintifffirstarrivedatthedefendantshospital,therewasa.75riskthattheavascularnecrosiscouldnotbeavoidedbypropertreatment.18Healsofoundthatbytheendofthefive-daydelaytheavascularnecrosiswasinevitable,i.e.,theprobabilityofits


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occurrencewasone.Onthesefiguresitisclearthat,ifthestandardofproofisthebalanceofprobabilities,thedefendantsnegligentdiagnosisshouldnotbetreatedasacauseoftheplaintiffsavascularnecrosis.Buttheplaintiffarguedthatthedefendanthadcausedhimtolosea.25chanceofavoidingavascularnecrosis,andthatthislostchanceshoulditselfbetreatedasdamagecompensableintort.Thisargumentwasacceptedbythetrialjudge(p.331) andbytheEnglishCourtofAppeal,butitwasultimatelyrejectedbytheHouseofLords.

The.75figurerepresentsthebackgroundrisk,atthetimetheplaintifffirstarrivedatthehospital,ofhiscontractingavascularnecrosis.The.25figurerepresentstheaugmentationoftheriskbroughtaboutbythedefendantsnegligentconduct.Althoughonecanspeak,ascourtsandlegalcommentatorstendtodo,ofthereducedorlostchanceofavoidingtheadversephysicaloutcome,Ishallinsteadrefertothisaugmentedprobabilityastheagent-imposedrisk.Iftheadversephysicaloutcomematerializes,itispossibletousetheantecedentriskfigurestocomputetheprobabilitythattheoutcomewascausedbytheagentsaction.InHotsonthefiguresforantecedentriskandexpostprobabilityofcausationcoincide,sincetheavascularnecrosishadbecomeinevitablebythetimepropertreatmentwasfinallyadministered.Butthisisaspecialcircumstancethatwillnotalwaysbepresent.19Ourconcernherewillalwaysbewiththeantecedentagent-imposedrisk,ratherthanwiththeexpostprobabilitythattheagentcausedthephysicaloutcome.Whilephysicalharmwas,onthespecialfactsofHotson,inevitable,thiswillnotalwaysbethecase.Itseemsclear,moreover,thatthestatusofagent-imposedriskasharminitselfshouldnotdependonwhetherthethreatenedphysicalharmhasmaterialized(solong,atleast,astheriskhasnotpassed).Onanappropriatesetoffacts,aHotson-typeclaimcouldthusbemadeevenintheabsenceofphysicalharm.

TheplaintiffsargumentinHotson,then,wasthattheagent-imposedriskwasitselfdamageofakinddistinctfromthephysicaldamage(inHotson,theavascularnecrosis).Whileremainingneutralforthetimebeingonwhetherthisargumentissound,letmerefertothenovelformofharmthattheplaintiffwasallegedtohavesufferedinHotsonasriskdamage.Toassesstheclaimthatriskdamageisatrueformofdamage,webeginbyaskingwhetheritisepistemicorobjectiveriskthatisinissuehere.Tothisenditwillbehelpfultoconsiderthecharacterizationofthelostchanceofavoidingavascularnecrosisinourterms,theagent-imposedriskthatwasacceptedinHotsonbytheHouseofLords:

[Counsel]whoappearedfortheplaintiffsaidthatinrelationtothefactsofthiscaseasfoundbythejudgewhatwasmeantbyachancewasthatif100peoplehadsufferedthesameinjuryastheplaintiff75ofthemwouldhavedevelopedavascularnecrosisofthewholefemoralheadand25wouldnot.This,hesaid,wasanassetpossessedbytheplaintiffwhenhearrivedattheauthorityshospital.Itwasthis(p.332) assetwhich[counsel]submitstheplaintifflostinconsequenceofthenegligentfailureoftheauthoritytodiagnosehisinjuryproperly.20

Thischaracterizationofagent-imposedriskisclearlyreminiscentoftheobjectiveconceptionofprobability,whichisconcernedwiththerelativefrequencyofanattribute


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withinareferenceclass.Heretherelevantattributeistheoccurrenceofavascularnecrosis,andthereferenceclassisthesetof(possible)personswhohavesufferedthesameinjuryastheplaintiff.Butsincetheriskfiguresaresimplythetrialjudgesestimateofthetruerelativefrequencies,theyarebestregardedasinstancesofepis-temic,notobjective,risk.Iftheestimatesturnedouttobeaccurate,epis-temicandobjectiveriskwouldcoincide;therelativefrequencyofavascularnecrosisinthereferenceclasswouldbe.25(objectiveprobability),andthatwouldbeafactofwhichwehadknowledge(epistemicprobability).Ofcoursethefigureforagent-imposedriskthatcomestobeacceptedinacaselikeHotsonmightnotcoincidewiththetruerelativefrequencyofharm.Thismighthappeneitherbecauseamistakeininductivereasoningoccurredorbecausetherewasinsufficientevidencetoensureareliableprobabilityjudgement.Inthecaseofamistakeininductivereasoningtheacceptedfigureforagent-imposedriskwouldnot,strictlyspeaking,beanepistemicprobability,sinceourdefinitionofepistemicprobabilityassumescompliancewiththemodesofreasoningsanctionedbythereasonablenessaccount.Forpresentpurposes,however,thereisnoneedtodistinguishbetweenthesetwowaysinwhichanacceptedriskfiguremightdifferfromtheobjectiverisk.

ThetrialjudgeinHotsonconcludedthat,onthefactsofthatcase,theagent-imposedriskwas.25.Asithappens,thereissomereasontothinkthathisestimatemighthavebeensubjecttoatleastoneofthetwoformsoferrorjustdiscussed.21Supposeforamomentthatthemistakewasaparticularlyegregiousone,andthatadelayoffivedayshasnosignificanteffectontheobjectivefrequencywithwhichinjuriesofthekindsufferedbytheplaintiffaretreatable.Theobjectiveagent-imposedriskwouldthenbezero.Ifthisfactsubsequentlycametolight,theclaimthatthedefendanthadcausedriskdamagetotheplaintiffwouldnolongerbeplausible.Thisstronglysuggeststhatriskdamagemustbeunderstoodintermsofobjective,notepistemic,risk.Thatishardlyasurprisingconclusion,sinceharminvolvesinterferencewithsomeaspectofwell-being,andsuchinterferencecanordinarilybeexpectedtohaveobjectiveexistenceinthephysicalworld.Inthisrespectphysicaldamageisaparadigmofharm.Butthepointthatriskdamagemustbeunderstoodintermsofobjectiveriskisnonethelessworthemphasizing,forthefollowingreason.Objectiveriskcannotbedirectlyobserved.Wemustalwaysrelyonourbestestimateoftheobjective(p.333) risk,usingwhateverevidenceistohand.Wenecessarilyoperate,inotherwords,withthenotionofepistemicrisk.Whileitistruethatonlyobjectiveriskcanplausiblybethoughttoconstituteaformofdamage,thefactthatwearelimitedtoobservingobjectiveriskthroughthelensofepistemicriskgivesrisetotheever-presentdangerofconfusingthetwo.

Thisbringsustothecentralquestionwemustanswer:isagent-imposedrisk,understoodinobjectiveandnotepistemicterms,properlyregardedasaformofdamageinitsownright?Forpurposesofillustrationletusassumethat,contrarytowhatinfactappearstohavebeenthecase,thetrialjudgesfiguresinHotsonof.75forthebackgroundriskand.25fortheagent-imposedriskwereaccurateestimatesoftheobjectiverisks.Cantheagent-imposedriskof.25plausiblybecharacterizedasadistinctformofdamage,distinguishablefromthephysicaldamagethatultimatelyoccurredinthe


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formofavascularnecrosis?Giventheassumptionthattherelevantfiguresrepresentobjectiveandnotjustepistemicrisks,itfollowsthatseventy-fiveof100personswhohadsufferedthesameinjuryastheplaintiff(tousethelanguageofLordMackayintheHouseofLords)wouldhavedevelopedavascularnecrosisevenifpropertreatmenthadbeenadministeredrightaway,whereastwenty-fivepersonswouldhaverespondedtotreatment.Theserelativefrequenciesmustberegardedasobjectivefactsaboutthephysicalworldwhichwouldholdevenifwehadnoknowledgeofthem.

Ourmainconcern,indeterminingwhetherriskdamageisatrueformofdamage,iswiththedefinitionofthereferenceclassintermsofwhichthepertinentrelativefrequenciesareexpressed.ThereferenceclassemployedinHotsonwasahypotheticalgroupof100representativepersonswhowereassumedtohavesufferedthesameinjuryastheplaintiff.Thisobviouslycannotmeanthattheinjuriesinthesamplegrouparetoberegardedaspreciselythesameineveryrespect.Whatmustbeintended,rather,isthatthe100injuriesallfallundersomegeneraldescriptionofphysiologicalstatesthathasnotbeenspelledoutindetailbutthatcould,ifnecessary,begivenamoreexplicitformulationbyreferencetotheplaintiffsconditionatthetimehewasinjured.Sincetheinformationthatcouldbeobtainedabouthisconditionwill,inevitably,beinatleastsomerespectsincomplete,thisdescriptionofphysiologicalstateswillnecessarilycoverarangeofcasesthatinvariousrespectsdifferfromoneanother.Forexample,sinceitwasnotknowninHotsonwhatproportionofthebloodvesselssupplyingtheplaintiffsepiphysishadbeenrupturedatthetimeoftheoriginalaccident,therelevantphysiologicaldescriptionwillsubsumeavarietyofcasesinwhichtheextentofdamagetothebloodvesselsrangesfromrelativelyminimaltorelativelysevere.Thesevariationsintheextentofinjurysustainedwillbereflectedinthesampleof100representativepersonsassumedtohavesufferedthesameinjuryastheplaintiff.

(p.334) Supposenowthatitwaspossiblesystematicallytodistinguishamongdifferentdegreesofblood-vesseldamageincasesofinjurysimilartotheonesustainedbytheplaintiffinHotson.Assumingforthemomentthatthereissomeknownandmoreorlessconstantthresholdofdegreeofdamagethatdistinguishestreatablefromuntreatableinjuries,itwouldthenbepossibletopartitionthereferenceclassof100personsintothetwenty-fivewhoweretreatableandtheseventy-fivewhowerenot.Wewouldalsoknowintowhichsub-classtheplaintifffell.Ifhefellintothetreatablesub-class,thenitwouldbepossibletosaythatthedefendant,innegligentlymisdiagnosinghisinjuryandsendinghimawaywithoutpropermedicalcare,hadcausallycontributedtothedevelopmentofavascularnecrosis.If,ontheotherhand,theplaintifffellintothesub-classofpersonswhoseinjurywasuntreatable,itwouldbepossibletosaythatthedefendanthadnotcausallycontributedtotheonsetofavascularnecrosis.Theclaimthattheplaintiffsufferedriskdamageatthehandsofthedefendantmust,ifitistobegenerallydefensible,becapableofsurvivingsuchapartitioningofthereferenceclass.Thepartitiondoesnot,afterall,callintoquestiontheoriginalriskfigures,whichhavebeenassumedtorefertoobjectiveprobabilities.TheonlydifferencebetweenthestateofaffairsthatobtainedinHotsonandthecircumstancewearenowenvisagingisthatwearesupposingwehavesufficientknowledgetodistinguishthetreatablefromtheuntreatablecases.But


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theclaimthattheplaintiffsufferedriskdamagemustsurelybeinde-pendentofpossessionofknowledgeofthiskind.

Infact,theclaimthattheplaintiffsufferedriskdamagebeginstolookquiteimplausiblewhenthetreatablecasescaninpracticebedistinguishedfromtheuntreatablecases.Iftheplaintiffsinjurywastreatable,thenthedefendantcausedhimphysicaldamage;thereisnoreasontosaythatitalsocausedhimanother,separateharmthattakestheformofriskdamage.If,ontheotherhand,theplaintiffsinjurywasnottreatable,thenthereisnoreasontosaythatthedefendantcausedhimanydamage,whetherwecallitphysicaldamageorriskdamage;wecannolongerplausiblymaintainthathelostachanceofavoidinganadversephysicaloutcome.Aswejustsaw,however,nothingshouldturnonwhetherwehavetheknowledgetodistinguishinpracticebetweenthetreatableandtheuntreatablecases.Ifthecausalprocessesinvolvedaredeterministicthenadistinctioncanbedrawninprin-ciplebetweenthetwocategoriesofcase,whetherwehavetheknowledgetodosoinpracticeornot,andsolongassuchadistinctionispossibleinprinciple,itmakesnosensetoclaimthattheplaintiffsuffered,atthehandsofthedefendant,apeculiar,non-physicalinjuryofthekindIhavelabelledriskdamage.Theassertionthattheplaintiffsufferedriskdamageissimplyafictionemployedtogetaroundthepracticaldifficultiesinvolvedindistin-guishingthetreatablefromtheuntreatablecases,i.e.,thedifficultiesinestablishingcausationwithrespecttothephysicalharm.

(p.335) Ihaveassumed,forthepurposesofthispartofthediscussion,thattheoriginalriskfiguresinHotsonof.75backgroundriskand.25agent-imposedriskinvolvedobjectiveprobabilities.Itisimportanttorecognize,however,thattheseprobabilities,likeallobjectiveprobabilities,arerelativefrequenciesthathavebeendefinedwithrespecttoacertainclassofpersons:theyarepropertiesofthoseclassesandnotofparticularindividualsliketheplaintiff.Butitisindividualswhoaresaidtosufferriskdamage,notclassesofpersons,andthereinliesthefallacyoftheclaimthatriskdamageconstitutesinjuryinitsownright.TheHotsonplaintiffslostchanceofavoidingavascularnecrosis,becauseitcannotbeconstruedasanaspectofthewell-beingofanindividual,cannotconstituteaninterestofthekindtortlawisconcernedtoprotect.Tocomeatthesamepointfromadifferentdirection,noticethattheplaintiffcannotbesaidtobelongtoasingle,canonicallydesignatedreferenceclassintermsofwhichtherelevantrisksmustbedefined.EvenwithrespecttothesingleincidentinHotson,theplaintiffbelongstoanindefinitelylargenumberofreferenceclasses.Suppose,forexample,thattheplaintiffsinjurywasuntreatable.Thenhebelongstothereferenceclassofpersonswithuntreatableinjuries,andthisissowhetherwecanidentifythosepersonsornot.Theprobabilityofdevelopingavascularnecrosisevenwithpropertreatmentis,withinthisreferenceclass,one,astateofaffairsthatisquitecompatiblewiththefactthatwithintheoriginalreferenceclass,consistingofpersonswithinjuriesvaguelysimilartotheplaintiffs,theprobabilityofdevelopingavascularnecrosisevenifpropertreatmentwereadministeredisonly.75.

Otherpossibilitiescaneasilybeimagined.EarlierImadethesimplifyingassumptionthatthereissomemoreorlessconstantthresholdofdegreeofblood-vesseldamagethat


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distinguishesthetreatableinjuriesfromtheuntreatablewithinthegeneralcategoryofinjuriesvaguelysimilartotheonetheplaintiffinHotsonoriginallysustained.Letmenowrelaxthisassumptionandsupposeinsteadthatthethresholdvarieswithanumberofdifferentfactors,someofwhichareknowntousandsomeofwhichareunknown.Thenvariouscombinationsofthesefactorswilldefinedifferentreferenceclasses,althoughofcoursewecanonlyrefertothoseclassesthataredefinedintermsoffactorswehappentoknowabout.Suppose,forexample,thattwoofthefactorsknowntousarebodyweightandbonestructure.Thenwecoulddefineareferenceclassconsistingofpersonswhosufferaninjuryofthesamegeneralkindastheplaintiffandwhoalsohaveabonestructureandbodyweightsimilartohis.Thisclass,whichwouldpresumablyoverlapboththeclassoftreatableinjuriesandtheclassofuntreatableinjuries,wouldhaveassociatedwithitanobjectiveprobabilityofinevitablydevelopingavascularnecrosis(i.e.,ofdevelopingthediseaseevenifgivenpropertreatment)thatwecouldexpecttobedifferentfromanyoftheotherprobabilitiessofarconsidered.Relaxingtheassumption(p.336) ofaconstantthresholddoesnot,ofcourse,affectourearlierconclusionthatsomeoneinthepositionoftheplaintiffinHotsondoesnotsufferanyharmthatcanplausiblybecharacterizedasriskdamage,sincewearestillsupposingthattherelevantcausalprocessesaredeterministic.Solongasthissuppositionholds,thetreatableinjurieswillbedistinguishableinprinciplefromtheuntreatable,andthisissoeventhoughthefactorsthatdetermineintowhichcategoryaparticularinjuryfallshavenowbeenassumedtoberelativelynumerousandcomplex.

Theconclusionthusfar,then,isthatiftheprocessesthatcausedormightinthefuturecausephysicalharmaredeterministic,thenthereisnobasisforsayingthatapersonwhohasbeenputatriskbyanotherofsufferingsuchharmhas,justbyreasonofbeingputatrisk,sustaineddamagedistinctinkindfromthephysicalharm.Inotherwords,incaseswheredeterminismholds,thereisnosuchthingasriskdamage.Thebasisforsayingthatapersonisatriskofsufferingacertaintypeofphysicalharmisthatheorshebelongstoaparticularreferenceclasswithwhichisassociatedaknownobjectiveprobabilityofharmofthattype.Butthereisnothingmag-icalabouttheparticularreferenceclassselected:generallyitwillsimplybethenarrowestclass,giventhecurrentstateofourknowledge,forwhichweareabletodeterminewithsomedegreeofaccuracytherelativefrequencyofthetypeofharminquestion.Ifwewereinapositiontodescribetheobjectiveprobabilitiesassociatedwithastillnarrowerreferenceclasstowhichweknewthepersoninquestionalsobelonged,presumablywewoulddoso.Moreoverweknow,giventheassumptionofdeterminism,thatitisinprinciplepossibletopartitionanysuchreferenceclassintotwosubclasses,oneforwhichtheprobabilityofphysicalharmisoneandoneforwhichtheprobabilityiszero.Thus,thereissimplynogroundfortheclaimthattheobjectiveprobabilityofharm,associatedwiththeparticularreferenceclassthatwearecurrentlyinapositiontodescribe,itselfconstitutesadistinctformofdamage.

Thenaturalquestiontoaskatthispointis,ofcourse,howtheanalysischangesifthecausalprocessesarenotwhollydeterministic.Theredoesnotseemtometobeanysimpleanswertothisquestion,andforpresentpurposesIwilllimitmyselftoafewobservations.First,ifaparticularobjectiveprobabilityofphysicalharmreflectsan


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indeterministiccausalprocess,sothatthereferenceclasswithrespecttowhichthatprobabilityisdefinedcannotbefurtherpartitioned,conductthathastheeffectofplacingsomeonewithinthereferenceclassinquestionmightperhapsbecharacterizedashavingcausedadistinctformofdamage.Thequestionisnotstraightforward,butconductthatplacessomeoneswell-beingatthemercyofanindeterministicrollofthediceseemsdistinguishablefromthesituationsdiscussedabove,wheretheassumptionwas,ineffect,thattherisk-imposerwouldeitherdefinitelycausephysicalharmorwoulddefinitelynotcause(p.337) physicalharm,butbecauseofimperfectknowledgewewouldnotbeinapositiontosaywhichofthesetwostatesofaffairsinfactobtained.Intheindeterministiccasethereseemstobeatruedetrimentalshiftinpositionthatissimplynotpresentinthedeterministiccase(unless,ofcourse,truephysicalharminfactiscaused).

Thesecondobservationisthat,whiletheremaythusbeasenseinwhichrisk-impositiondoesconstitutedamageinitself,theadvocatesoftheriskdamagethesishavenotdistinguishedbetweenthedeterministicandindeterministiccases.Moreoverinmanyofthefactsituationsinwhichriskdamagehasbeenalleged,thecausalprocessesatworkseemmorelikelytohavebeendeterministicthanindeterministicincharacter.ThisistrueofHotson,forexample,wheretheHouseofLordsmadetheveryplausibleassumptionthatatthetimetheplaintiffarrivedatthehospitaleitherenoughbloodvesselswerestillintacttomakehisinjurytreatable,orenoughhadbeendestroyedtomakeavascularnecrosisinevitable.22

ThethirdandfinalobservationIwouldmakeonthetopicofindetermin-ismisthatjustbecausethecausalprocessesunderlyingagiventypeofeventare,inpartoratsomelevel,indeterministic,itdoesnotfollowthatanyriskassociatedwithsuchaneventshouldbetreatedasdamageinitself.Itseemsclear,forexample,thattrueindeterminismexistsatthelevelofsub-atomicparticles,butthereissomereasontothinkthatrandomdeviationsindifferentdirectionscompensateforoneanother,ineffectwashingindeterminismoutofthesystematthemacroscopiclevel.Ifthatwerethecasetheninter-actionsamongwhatJ.L.Austincalledmedium-sizeddrygoodswould,forallintentsandpurposes,bedeterministicincharacter.23Thereisclearlymuchmoretobesaidabouttherelationshipbetweencausalindeterminismandthethesisthatrisk-impositionisdamageinitself,buttheseobservationsshouldatleastengendercaution.Evengivenourknowledgethatindeterminismexistsintheworld,wegenerallydonothavereasontotreattheobjectiveprobabilitiesweencounteronaneverydaybasisasanythingotherthanincompletedescriptionsofessentiallydeterministicevents.24

Torepeat,mymainconclusioninthissectionisthat,atleastinthecaseofeventsinvolvingdeterministiccausalprocesses,thereisnosuchthingasriskdamage.25Itisimportant,however,toemphasizetherelatively(p.338) modestnatureofthisconclusion.Ihavearguedthatriskdoesnotgenerallyconstitutedamage,butnotthatthereisnosuchthingasrisk:probabilityinbothitsepistemicandobjectivesensesisameaningfulconcept,andriskisstraightforwardlydefinedintermsofprobability.NorhaveIarguedthatliabilityintortshouldnotbeimposedforriskcreationassuch.Tosupportthatconclusionafurtherpremiseisrequired,totheeffectthattortliabilityshouldonlybeimposedinorderto


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compensatefordamagecaused(inabut-fororNESSsense).Iamgenerallypreparedtoacceptthisclaim,orsomethinglikeit,butIhavenotarguedforithere,andthequestioncanhardlyberegardedasuncontroversial.Suchapremisewouldberejectedbymanydeterrencetheorists,forexample,includinginparticularmanywhoacceptaneconomicinterpretationoftortlaw.26

Finally,IhavenotarguedthatthereshouldnotberecoveryintorteveninacaselikeHotsonitself.Ihavesimplyarguedthatthelostchanceof.25ofnotdevelopingavascularnecrosisshouldnotberegardedasdamageinitsownright.Therecould,however,bepsychologicalharmthatoccurswhentheplaintiffinacaselikeHotsondiscoversthatheorshehasnot(p.339) receivedpropertreatment,andperhapsthisshouldbelegallycompensable.27Moreimportantly,thereisaveryplausibleargumentthatthelostopportunitytoreceivepropermedicaltreatmentisadistinctformofharminitsownright.28WhentheplaintiffinHotsonleftthehospitalaftertheinitialmisdiagnosis,hewasrelyingonthedefendantssupposedskillandcompetenceindiagnosingandtreatingleginjuries,andifhehadhadanyreasontodoubttheircompetencehepresumablywouldhavegoneimmediatelytodifferentdoctors.Asaresultofthisreliancehelosttheopportunitytoreceivepropertreatmentatatimewhentherewas,accordingtoourbestpresentknowledge,atleastsomechance,howeversmall,thathemighthavemateriallybenefitedfromit.The.25lostchanceofavoidingavascularnecrosismightthenberegarded,notasdamageinitself,butasevidencebearingonthevaluationofthelostopportunity.29

Itis,inmyview,nocoincidencethatthetortcasesinwhichtheriskdamagethesishaswonanydegreeofjudicialacceptancehaveallbeenmedicalmalpracticeactionswhereitwasplausibletothinkthattherehadbeenbothreliancebytheplaintiffandconsequentlostopportunity.Wemustatleastconsiderthepossibilitythattheapprovingjudgesreallyhadinmindthenotionoflostopportunity,notlostchanceorrisk,or,perhapsmoreplausiblyinthemajorityofcases,thattheysimplyfailedtodistinguishbetweenthesetwonotions.SofarasIamaware,thereisnocaseinwhichriskhasbeentreatedasdamageinitselfoutsidethecontextofapre-existingcon-sensualrelationshipinvolvingreliance.Ifriskcreationtrulyisaformofdamageinitsownright,itshouldbepresenteveninastrangercaseinvolving,say,ariskofdiseasearisingfromexposuretoatoxicelement.Buttheclaimthatriskisadistinctformofdamageappearsnottobeadvancedonfactssuchasthese.

III.RiskandResponsibilityforPhysicalHarmIf,aswasarguedintheprecedingsection,riskcannotberegardedasharminitsownright,thenitisnaturaltothinkthatmoralresponsibilityforriskybehaviorshouldtaketheformofresponsibilityforthephysicalharm,ifany,thatwasunintentionallycausedbytheconductinquestion(assuming,ofcourse,thattheharmfallswithintherisktheconductcreated).Wemightalsoconsiderthepossibilitythatsomeoneshouldbeheldmorally(p.340) responsibleforsimplyengagingintheriskybehavior,quiteapartfromwhetherharminfactensues,butsinceourpresentconcerniswithtorttheoryratherthancriminaltheoryIshalllimitdiscussiontoresponsibilityforphysicalharmthatanagents


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conducthasactuallycaused.Sinceitwillnotbepossibleinthepresentchaptertoconsiderthisissueatanylength,Ishallconcentrateonclarifyingtheproperunderstandingofriskwithinatheoryofresponsibilityforcausingharm,drawingontheaccountofrisksetoutinsectionI.Wemustconsidertwopossibilities:first,thatresponsibilityforphysicalharmisconcernedwithconductthatwasriskyintheobjectivesense,andsecondly,thatsuchresponsibilityisconcernedwithconductthatwasriskyintheepistemicsense.

Objectiveprobability,andhenceobjectiverisk,isdefinedintermsoftherelativefrequencyofanattributewithinareferenceclass.Riskinthissenseexistswhetherweknowaboutitornot.Responsibilityforharmresultingfromconductthatwasriskyintheobjectivesensecannot,therefore,dependonantecedentknowledgeorforeseeability.Responsibilityofthiskind,ifitexists,isequivalenttoresponsibilitydeterminedsolelybythefactthatonesconductcausedharm,sinceifaparticularactioncausesharmitmustfallwithinoneormorereferenceclassesforwhich,whetherornotweareinapositiontodescribethoseclasses,therelativefrequencyoftherelevanttypeofharmisgreaterthanzero.Translatedintotortterms,suchresponsibilitywouldamounttoaformofstrictindeed,absoluteliability.Absoluteliabilityisoftendescribedasamatterofactingatonesownperilorrisk;astheprecedingdiscussionmakesclear,itisobjectiveriskthatisatissuehere.

Thestrongestandmostinfluentialargumentforabsoluteliabilityhasoftenbeenputforwardbylibertarians,anditfitstogetherinanaturalwaywithlibertarianpoliticalphilosophy.30Ishallaccordinglycallitthelibertarianargument.TheessentialideaisthatifIchoosetoactintheworld,IambothfullyentitledtowhatevergainsImaymakeandfullyresponsibleforwhateverharmsImaysufferorcause.Theclaimaboutgainsleadstothestandardlibertarianthesisthatforcedredistributionisingeneralille-gitimate.Theclaimaboutharmisthebasisofthelibertariandefenceofastandardofabsoluteliabilityintortlaw.Bothclaimsarepremisedonacertainunderstandingofthemoralsignificanceofaction.Ihaveachoiceabout(p.341) whethertobecomeactiveintheworld,andifIchooseactionoverpassivitythenallsubsequentconsequences,bothgoodandbad,areappropriatelychalkeduptomymoralledgerandnooneelses.Thusotherpersonsarenotentitledtoshareinwhatevergainsmayaccruetomeasaresultofmyactivity,31butbythesametokenIcannotforcepassiveby-standerstoabsorbanylossmyactivitiesmaycreate.Ineconomicjargon,agentsareproperlycompelledtointernalizethelossestheycauseothers.Indistinguishingasitdoesbetweenactivityandpassivity,thelibertarianargumentthussupposesthatmoralconsequences,bothgoodandbad,attachnotjusttoadecisiontoactinthisorthatway,buttoadecisiontoacttoutcourt.

InTheCommonLawHolmescriticizedwhatisrecognizablyaversionofthelibertarianargument,whichheformulatedinthefollowingway:

Everyman,itissaid,hasanabsoluterighttohisperson,andsoforth,freefromdetrimentatthehandsofhisneighbors.Inthecasesput,theplaintiffhasdonenothing;thedefendant,ontheotherhand,haschosentoact.Asbetweenthetwo,thepartywhosevoluntaryconducthascausedthedamageshouldsuffer,rather


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thanonewhohashadnoshareinproducingit.32

Themainelementsofthelibertarianargument,includinginparticularthedistinctionbetweenactivityandpassivity,areclearlypresenthere.ButHolmesrejectedtheargument,notjustongroundsofpolicypolicymeaning,forHolmes,utilitarianconsiderationsbutalsobecauseitoffend[ed]thesenseofjustice.33TheinitialpremiseofHolmescounter-argumentisthatthereasonformakingtheperformanceofanactarequirementofliabilityintortistoensurethatthedefendantshouldhavemadeachoice.34Thispremiseis,ofcourse,alsooneofthestarting-pointsofthelibertarianargument.ButthenHolmescontinues:theonlypossiblepurposeofintroducingthismoralelementistomakethepowerofavoidingtheevilcomplainedofaconditionofliability.Thereisnosuchpowerwheretheevilcannotbeforeseen.35AtthispointHolmesisclearlyintroducingadifferentunderstandingofthemoralsignificanceofaction.Itisnotchoiceassuchthathasmoralsignificance,butratherchoiceaccompaniedbythepowertoavoidtheresultingconsequence.Thecapacitytoavoidtheresult,ratherthanthemerefactofhavingvoluntarilychosentoact,iswhatgivesrisetomoralresponsibilityforharm.

ButwhyshouldweacceptHolmesclaimthatitisavoidabilityoftheconsequence,ratherthanthechoicetoactassuch,thatgivesrisetomoralresponsibilityforphysicalharm?Holmeshimselfhaslittletosayonthis(p.342) point,buthedropsahint,almostinpassing,inhissubsequentdiscussionoftheargumentfrompolicy:Amanneednot,itistrue,dothisorthatact,thetermactimpliesachoice,buthemustactsomehow.36Thissug-geststhatHolmesrejects,atleastsofarasinjurersareconcerned,thedistinctionpresupposedbythelibertarianargumentbetweenactivityandpassivity.Thuswemightreconstructhiscounter-argumentinthefollowingway.Thelibertarianargumentsupposesthatmoralsignificanceattachestoadecisiontoactassuch,becauseitsupposesthatpersonshaveatruechoiceconcerningwhethertobeactiveorpassivebeings.Butinfactthereisnosuchchoice:thehumanconditionissuchthateveryonemustchoosetoactinsomewayorother.37Giventhateveryonemustbeactive,nomoralconsequencescanattachtoactionperse.Somethingmoreisthereforerequiredtogroundresponsibilityforcausingharm,andthatfurtherrequirementismostplausiblythoughttobeacapacitytoavoidtheharm.Buttherecanbenosuchcapacityunlesstheagentiscapableofforeseeingtheresult.AsHolmesfamouslyputit,[a]choicewhichentailsaconcealedconsequenceisastothatconsequencenochoice.38

Itispossibletotakethislineofthoughtfurther.Thelibertarianargumenttreatsinjurersasactiveandvictimsaspassive,ineachcasebychoice.Holmesrespondsthatinjurersarenecessarilyactive,notactivebychoice,becauseactivityisinevitable.Butifthatisso,thenvictimsmustbecharacterizedasactiveandnotjustinjurers.Thisis,inessence,thepointmadebyCoasewhenhewrotethat[i]fwearetodiscusstheproblem[ofharmfulinteractionsbetweentwopersons]intermsofcausation,bothpartiescausethedamage.39Thelibertarianargumentassumesthatonepersonisthecauseofharmtoanother,wheretheimageisofadominant,activepartyactinguponasubordinate,passiveparty.Coasewasrespondingtoasimilarimageembodiedinthereceived


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economicwisdomthatsocialcostsshouldbeinternalizedtotheactivitythatcausedthem.Inadditiontoarguingthat,fromaneconomicpointofviewsocialcostsare,undercertaincir-cumstances,bestdealtwithbyprivatemarkettransactions,Coasealsomaintainedthatthisimageofonepartyactingupontheotherisprofoundlymisleadingandshouldberejected.Instead,hesuggested,wemustseetheharminquestionashavingbeencausedbytheinteractionoftwoactivepartiesinotherwords,astheproductoftwoactivities,andnotjustone.Thustheinjurythatresultswhenamotoristrunsdownapedestrianshouldnotberegardedashavingbeencausedbyonepersonactingunilaterally(p.343) uponanother,butratherastheupshotoftwodecisionstoact:themotoristsdecisiontodrivewhen,whereandhowshedid,andthepedestriansdecisiontowalkwhen,whereandhowhedid.

Theimageassociatedwiththelibertarianargumentofone,activepartywhoexertsforceagainstanother,passivepartyisoftenbuttressedbyananalogywithpropertyrights,andinparticularrightsinland.40RobertNozicksmetaphorofalineorboundarythatcircumscribesanareainmoralspacearoundanindividualdrawsattentiontothisanalogyinaparticularlyvividway.41Aviolationofindividualrightsisequatedwithaborder-crossing,andthisnotionisequatedinturnwith,essentially,causingharm.Buttheanalogywithaphysicalbordermustultimatelybecashedoutintermsofthedistinctionbetweenanactiveinjurerandapassivevictim,andboththeHolmesianandCoaseanargumentscallthisdistinctionintoquestion.Inaddition,theCoaseanargumentunderminestheclaimthatonecanpickoutoneofthepartiestoaharmfulinteractionasthecauseoftheharm.

IhavearguedelsewhereforanunderstandingofharmfulinteractionandcausationthatisconsistentwiththeviewsofbothHolmesandCoase,42andIneednotrepeatthatdiscussionhere.ThepointIwishtoemphasizeforpresentpurposesisthis.Thelibertarianargument,ifitwerevalid,wouldjustifyaformofmoralresponsibilitythatwastriggeredbythematerializationofanobjectiverisk.Butinmakingforeseeabilitythetouchstoneofresponsibilityforcausingharm,Holmesisimplicitlyinvokinganotionofepistemicrisk.Foreseeabilityisafunctionof(possiblyincompleteoronlypartiallyaccurate)knowledgeofrelativefrequencies,notofrelativefrequenciestoutcourt.AsHolmesmakesclear,thekeymoralconcepthereisavoidability:thepointofmakingforeseeabilityarequirementofresponsibilityforphysicalharmisthatanagentisunabletoavoidharmunlessheorshecanforeseeit.Intheabsenceofforeseeability,theharmissimplytheunfortunateupshotofaninteractionbetweentwopersons.Thereisnoreasoninjusticetoshiftthelossfromwhereitfell,sincethereisnobasisformorallyattributingtheharmtoonepartyratherthantheother.

Thereasonablenessaccountofepistemicprobabilitymaintainsthatsuchprobabilitiesareestimationsofrelativefrequencythathavebeenmadeinaccordancewithacceptedstandardsofinductivereasoningandrationalbelief.Epistemicprobabilityjudgements,insofarastheypresupposeinter-subjectivelyvalidstandardsofreasoning,canbecharacterizedasobjective.Butitisnaturaltosaythatavoidability,asamoralconcept,mustlooktoasubjectivecapacitytoavoidharm,andhencetoasubjectivecapacityto


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(p.344) foreseeit.Howcanthispointbereconciledwiththeobjectivityofthereasonablenessaccount,and,indeed,withthesimilarlyobjectiveunderstandingofforeseeabilityinnegligencelaw(reasonableforeseeability,inthelanguageoftort)?Thisissuecannotbeexaminedindetailhere,butthebriefansweristhatwearedealingwithanumberofdifferentconceptionsoftheobjective/subjectivedistinction.

Thenotionofreasonableforeseeabilityintortlawisobjectiveinitscontent:thelawsdeterminationofwhichrisksmustbeforeseenbyanagentisbasedupon,amongotherthings,anappropriateinterpretationofthereasonablenessaccountofepistemicprobability(moreparticularly,aninterpretationexpressedintermsofthejudgementsofanordinaryorreasonableperson).Thestandardofduecareinnegligencelawissimilarlyobjectiveinitscontent:theprecautionsthelawrequiresinagivensituationofriskaredeterminedbywhatareasonableperson,ratherthantheindividualdefendant,thinksshouldbedone.Butnormsarealmostalwaysobjectivesofarastheircontentisconcerned;itisnotuptotheindividualagenttodecidewhatconstitutes,say,murder.Thenotionsofreasonableforeseeabilityandduecarearealsoobjectiveinanothersense,whichisthatneitherrequiresadvertence:theindividualagentneednotbeaware,ontheparticularoccasion,eitherthatheiscreatingunreasonablerisksortakinginadequatepre-cautions.Thisis,ofcourse,animportantformoftheobjective/subjectivedistinctionincriminallaw.

Butobjectivityregardingcontentandadvertenceisperfectlycompatiblewithsubjectivityregardingcapacity,atleastsolongasweunderstandcapacityinacertainway.AccordingtotheviewIhaveinmind,whichIcannotdefendherebutonlysketchinveryabbreviatedform,capacitytoforeseeandavoidharmisappropriatelyunderstoodasageneralabilitythattheindividualwhocausedagiveninjuryordinarilysucceedsinexer-cisinginother,similarsituations.43Whetherthepersonwascapableofforeseeingandavoidingtheharmontheparticularoccasionmayormaynotbeameaningfulquestion,buteitherwayitisthegeneralcapacitythatmatterssofarasmoralresponsibilityisconcerned.Thenecessaryassumption,then,isthatmostpeople,acrossawidevarietyofcircumstances,havethegeneralcapacitytoforeseeandavoidharmthatthelawattributestotheordinaryorreasonableperson.TheresultisaformofresponsibilityforunintentionalharmthatIcall,borrowingatermfrom(p.345) TonyHonor,outcome-responsibility.44Thekeymoralconceptthatunderpinssuchresponsibilityis,asHolmessuggested,avoidability.Itcanbecontrastedwiththecentralformofresponsibilityincriminallaw,forwhichthelabelculpabilityisappropriate:herethekeymoralconceptisanintentiontoharm,oratleastasubjectiveawarenessthatharmwillormightoccur.Obviouslytheseconceptionsofresponsibilitycanoverlap,sincethereisnoreasontodenythatapersonwhoisawareoftheriskheorsheiscreatingisoutcome-responsiblefortheresultingharmiftheriskmaterializes.Butthetwoconceptionsofresponsibilityarenonethelessdistinct:outcome-responsibilityis,amongotherthings,generallylessblameworthythanculpability.

Outcome-responsibility,likethelibertarianconceptionofabsoluteliabilityconsideredearlier,focusesonresponsibilityforharmfuloutcomesratherthanonresponsibilityfor


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actionassuch.Butitdiffersfromthelibertarianconceptioninthatitdoesnotautomaticallycallforanagenttowhomresponsibilityforharmisbeingattributedtopaycompensation.Outcome-responsibilityaffectsreasonsforactioninamorediffusefashion:inagivensituationitmayrequiretheagenttoapologize,forexample,ortoobtainassistance.Italsoconstitutesthebasisforamoralobligationtocompensate,butinorderactuallytoestablishsuchanobligationfurtherargumentisnecessary.Ingeneral,then,outcome-responsi-bilitycanserveasthemoralfoundationintortlawforeitheranegligencestandardofcare,orforadanger-basedstandardofstrictliabilitysuchastheruleinRylandsv.FletcherortheAmericanruleforultrahazardousactivities,sincebothkindsofliabilitypresupposereasonableforeseeabil-ity.Buttheconsiderationsthatbearonthechoicebetweentheseliabilityrules,aswellasontheirmorespecificformulation,aremattersthatmustbelefttoanotheroccasion.

IV.ConclusionRiskisacentralconceptinbothtortlawandtorttheory.InthisessayIhavearguedthatitisimportanttodistinguishbetweenanobjectiveandanepis-temicconceptionofrisk.Theformerisgroundedinthestandardrelative-frequencyaccountofprobability,whilethelatterisconcernedwiththeevidentiarybasisforjudgementsorestimationsofrelativefrequency.Thecommonlyheldthesisthatriskisharminitselfismostplausiblyexplicatedintermsoftheobjectiveconceptionofrisk.Butevenunderthisfavorableinterpretationthatthesismust,Ihaveargued,berejected.Moralresponsibilityfortheconsequencesofriskyconductshouldbeunderstoodnotasresponsibilityforcreatingarisk,butasresponsibilityfortheunintentionalphysicalharm,ifany,thatensues.Suchoutcome-responsibilitycan,however,(p.346) onlyplausiblybeattributedtoapersonifhisorherconductwasriskyintheepistemicandnotjustintheobjectivesense.Thissuggestsinturnthatwithinatheoryoftortlawbasedonnotionsofinterpersonaljusticeandindividualresponsibility,foreseeabilityofharmoughttobeconsideredanecessaryconditionofliability.

Notes:(1)ForpurposesofthischapterItreatthetermsharm,injury,anddamageassynonymous.Insomecontexts,however,itisappropriatetoassignthemdistinctmeanings.SeeStephenR.Perry,TheMoralFoundationsofTortLaw,11IOWAL.REV.449,498(1992).

(2)Foranexcellentoverview,seeROYWEATHERFORD,PHILOSOPHICALFOUNDATIONSOFPROBABILITYTHEORY(1982).

(3)See,e.g.RUDOLFCARNAP,LOGICALFOUNDATIONSOFPROBABILITY(2ded.1962),1951;DAVIDLEWIS,ASubjectivistsGuidetoObjectiveChance,in2PHILOSOPHICALPAPERS(1986)83.

(4)IANHACKING,THEEMERGENCEOFPROBABILITY(1975),1223.

(5)SeeparticularlyRICHARDVONMISES,PROBABILITY,STATISTICS,ANDTRUTH(1957);HANSREICHENBACH,THETHEORYOFPROBABILITY(1949).


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(6)SeeJosephFord,HowRandomisaCoinToss?,36PHYSICSTODAY40(April1983).Fordmaintainsthatacointossispredictableinthesensethatitisdescribablebyafinitealgorithm.Butitisunpredictableinthesensethatthedescriptionoftheinitialconditionrequires,becausechaoticprocessesareinvolved,aninfiniteamountofinformation.

(7)Itshouldbenotedthateventhosetheoristswhomaintainthatarelative-frequencytheoryistheonlydefensibleaccountofprobabilitymuststillacknowledgethedistinctionbetweenanactualfrequencyinthephysicalworldandourestimateorapproximationofthatfrequency.Cf.WEATHERFORD,supra,note2,at1312,142,177.Thisdistinctioncreatessufficientlogicalroomtopermitinfact,torequirethedevelopmentofanepistemicconceptionofprobabilityalongthelinesofthereasonablenessaccount.

(8)Presumablyonecouldalsoregardtheresultingprobabilityjudgementasanexpressionofthedegreeofrationalbeliefthatiswarrantedintheconclusionthatthepropertywhoserelativefrequencyisbeingconsideredwillbeinstantiatedinagivencase.

(9)F.P.Ramsey,TruthandProbability,inFOUNDATIONS:ESSAYSINPHILOSOPHY,LOGIC,MATHEMATICS,ANDECONOMICS(D.H.Mellor(ed.),1978),58.Forversionsofradicalsubjectivism,see1BRUNODEFINETTI,THEORYOFPROBABILITY:ACRITICALINTRODUCTORYTREATMENT(1974);LEONARDSAVAGE,THEFOUNDATIONSOFSTATISTICS(1954),2768.

(10)DeFinetti,oneoftheleadingradicalsubjectivists,formulatedhiscentralthesisinuppercaseletters:PROBABILITYDOESNOTEXIST:DEFINETTI,supra,note9,atx.

(11)SeeJOHNM.KEYNES,ATREATISEONPROBABILITY(1921);CARNAP,supra,note3.Thethreemostinfluentialgeneraltheoriesofprobabilityaretherelative-frequencytheory,thesubjectivisttheory,andthelogical-relationtheory.

(12)Itshouldbeemphasizedthatprobabilitystatementsarenotregardedasobjectiveinthesensepresupposedbyarelative-frequencytheory,i.e.,theyarenotunderstoodasexpressingfactsaboutthephysicalworld.Theyare,rather,supposedtobeobjectiveinanapriori,non-empiricalsense:foreachpossiblesetofevidentiarypremises,whethertrueornot,andforeachconclusionaboutthewaythingsmightbethatcanbeformulatedinthelanguage,thereisalogicallycorrectprobabilityjudgementthatinprincipleisspecifiableapriori.

(13)WEATHERFORD,supra,note2,at236.

(14)Itbearsmentionthatsomesubjectivists,whileclaimingthatwedonotnecessarilyhaveknowledgeofobjectiveprobabilities,dononethelessacceptthattherearepragmaticstandardsforassessingequallycoherentprobabilityjudgementsasbetterorworse.ThesestandardsInvolveaproperrespectforfrequencies,arisingfromaproperrespectforinduction:SimonBlackburn,OpinionsandChances,inPROSPECTSFORPRAGMATISM:ESSAYSINMEMORYOFF.P.RAMSEY(D.H.Mellor(ed.),1980),175,


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195.

(15)Keynes,theothermainproponentofalogicalrelationunderstandingofprobability,tookaverydifferentapproachfromthatofCarnap:seeKeynes,supra,note11.Keynesheld,perhapsundertheinfluenceofG.E.Moore,thatwehavethecapacitydirectlytoperceiveorintuitprobabilityrelations.Thisledhimtomaintain,amongotherthings,thatsomeprobabilitiesarenon-numericalandsomenon-comparative.Thisapproachobviouslytiesprobabilityjudgementsmuchmorecloselytoactualhumancapacities,butitdoessoatthecostofrenderingproblematicthethesisthatsuchjudgementsarelogicalincharacter.

(16)SeeJosephH.King,Jr.,Causation,ValuationandChanceinPersonalInjuryTortsInvolvingPreexistingConditionsandFutureConsequences,90YALEL.J.1353(1981);RichardW.Wright,CausationinTortLaw,73CAL.L.REV.1735,181416(1985);WILLIAMM.LANDESandRICHARDA.POSNER,THEECONOMICSTRUCTUREOFTORTLAW(1987),263;JaneStapleton,TheGistofNegligence,pt.2,104L.Q.R.389(1988);Herskovitsv.GroupHealthCoop,ofPugetSound,664P.2d474(Wash.1983)(Pearson,J.,concurring);DeBurkartev.Louvar,393N.W.2d131(Iowa1986);Hotsonv.EastBerkshireAreaHealthAuthority[1987]2W.L.R.287,revd.[1987]A.C.750;Lawsonv.Laferriere,R.J.Q.27(Quebec1989),revd,[1991]1S.C.R.541(Can.).

(17)[1987]2W.L.R.287,revd.[1987]A.C.750.Ihavecriticizedthethesisthatriskconstitutesharminitself,alonglinessimilartotheargumentpresentedinthissection,inStephenR.Perry,ProtectedInterestsandUndertakingsintheLawofNegligence,42U.TORONTOL.J.247,25262(1992).

(18)ForthesakeofconvenienceinexpositionIshallhenceforthusethetermsriskandprobabilitymoreorlessinterchangeably.Givenourearlierdefinitionofriskasthemathematicalexpectationofharm(PH),thisamountstoanassumptionthatH=1.

(19)Ingeneral,ifAistheagent-imposedriskandBisthebackgroundrisk,theexpostprobabilitythattheagentcausedtheoutcomeisA/(A+B).TheexpostprobabilitythatafactorcontributingtothebackgroundriskcausedtheoutcomeisB/(A+B).InHotsonthefiguresforantecedentriskcoincidewiththoseforexpostprobabilityofcausationbecauseA+B=1.

(20)Hotson[1987]1A.C.at783,perLordMackay.

(21)Id.at785.

(22)Hotson[1987]1A.C.at785,perLordMackay.

(23)HansReichenbach,oneofthemainproponentsoftherelativefrequencytheoryofprobability,heldathesisalongtheselines:seeHANSREICHENBACH,ATOMANDCOSMOS:THEWORLDOFMODERNPHYSICS(1933),278;WEATHERFORD,supra,note2,at181.


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(24)Itisworthremarkingthatthebasictestsofcausationintortlaw,namely,thebut-fortestanditsmoresophisticatedvariant,theNESStest,bothappeartopresupposedeterminism.Thisisimplicitinthenotionofnecessitythateachtestindifferentwaysincorporates.FordiscussionoftheNESStest(NecessaryElementofaSufficientSet),seeWright,supra,note16.

(25)MentionshouldbemadeofSindellv.AbbottLab.,607P.2d924(Cal.1980),sincethereisasenseinwhichthatcaseimposedliabilityforriskcreation(asmeasuredbymarketshare).

TheunderlyingrationaleinSindell,however,wastoensurethateachofagroupoftortfeasorspaysoutcompensatorydamagesequivalenttothetotalamountoftortiousphysicalharmthatthattortfeasorcanbeexpectedtohavecausedinadefinedcategoryofcase.Sinceriskisnotbeingtreatedasdamageinitsownright,butratherasanindicatoroftotalphysicalharminacategoryofcases,therationaleofthecaseisnotcalledintoquestionbymyargumentshere.Itisworthnotingthatthetotal-physical-harmrationaleformarketshareliabilitywasrejectedinHymowitzv.EliLilly&Co.,539N.E.2d1069(N.Y.1989),whereajustificationbasedonculpabilitywasacceptedinstead.ForthatreasonHymowitzisamoreproblematicdecisionthanSindell.Avariantonthetotal-physical-harmrationaleofSindellwassuggestedbyWeinstein,C.J.,inInreAgentOrangeProductLiabilityLitigation,597F.Supp.740,8339(E.D.N.Y.1984).GiventheimpossibilityofsortingoutwhichindividualshadcontractedcancerfromAgentOrangeandwhichfrombackgroundrisks,theproposalwas,inessence,thatallcancervictimsintherelevantgroupmightbeabletorecoverashareoftheirdamagesproportionaltotheincreaseintotalriskcreatedbytheagent-imposedrisk.Theamountthedefendantwouldhavetopayoutshouldberoughlyequivalenttothephysicalharmithadactuallycaused.

(26)Thatriskshouldasamatterofcorrectivejusticebecompensableassuch,evenintheabsenceofphysicalharm,istheultimateconclusionofadebatebetweenChristopherSchroederandKenSimons.SeeChristopherH.Schroeder,CorrectiveJusticeandLiabilityforIncreasingRisks,37UCLAL.REV.439(1990);KennethW.Simons,CorrectiveJusticeandLiabilityforRisk-Creation:AComment,38UCLAL.REV.113(1990);ChristopherH.Schroeder,CorrectiveJustice,LiabilityforRisks,andTortLaw,38UCLAL.REV.143(1990).NeitherSchroedernorSimonsexplicitlystatesthatriskisharm,butwithoutthispremisetheconclusionthatriskiscompensableoncorrectivejusticegroundsisnotveryplausible.GlenRobinsonalsoholdsthatriskshouldbecompensable,buthisdiscussionisambiguousastowhetherriskisproperlytreatedasharminitself.GlenO.Robinson,ProbabilisticCausationandCompensationforTortiousRisk,14J.LEGALSTUD.779(1985).LANDESandPOSNER,supra,note16,at263,expresslymaintainthatriskcanbetreatedasaformofharm,butonthedeterrencetheorytheydefendthispremisedoesnotappeartoberequiredinordertoargueforthecompensabilityofriskassuch.LandesandPosnersdiscussionofprobabilityisconfused,inmyview,byafailuretodistinguishobjectivefromepistemicprobability.Seeparticularlyidat2349.


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(27)SeeLawsonv.Laferriere,[1991]1S.C.R.541,558(Can.);Ayersv.TownshipofJackson,525A.2d287,295(N.J.1987).

(28)Seefurther,Perry,supra,note17,at30816.

(29)Italsoseemsreasonabletothinkthatmedicalexpensesincurredtoavoidorminimizeaknown,agent-imposedriskofsufferingphysicalharminthefutureshouldberecoverableintort.Liabilityforpureeconomicloss,whichasageneralmattergivesrisetodifficultiesinneg-ligencelaw,isnotproblematicinthiscontext.SeePerry,supra,note17,at2679.

(30)AversionofthelibertarianargumentwasputforwardbyBaronBramwell,a19thcenturyEnglishjudgeknownforhislaissez-faireideology,inBamfordv.Turnley,122E.R.27,33(Ex.Ch.,1862).InhisearlyworkintorttheoryRichardEpsteinadvancedanargumentverysimilartoBramwells.SeeRichardA.Epstein,ATheoryofStrictLiability,2J.LEGALSTUD.151,1578(1973);RichardA.Epstein,IntentionalHarms,4J.LEGALSTUD.391,398(1975).FordiscussionofEpsteinsversionoftheargument,seeStephenR.Perry,TheImpossibilityofGeneralStrictLiability,1CAN.J.L.&JURIS.147,14859(1988).ThelibertarianargumentseemsalsotobeimplicitlypresupposedbyRobertNozick,sinceheassumesthatanobligationtocompensatearisessimplyfromcausingharm.SeeROBERTNOZICK,ANARCHY,STATE,ANDUTOPIA(1974),71.

(31)Thestatusattributedbythelibertarianargumenttopositiveexternalities,i.e.,benefitsthatflowfromtheagentsconductbutthataccruetootherpersons,isnotentirelyclear.

(32)OLIVERWENDELLHOLMES,JR.,THECOMMONLAW(1881),84.

(33)Id.at96.

(34)Id.at95.

(35)Id.

(36)OLIVERWENDELLHOLMES,JR.,THECOMMONLAW(1881),at95.

(37)Avariantoftheargument,whichHolmeswouldprobablynotaccept,wouldaddthatevenadecisiontoremainmotionlessis,preciselybecauseitisavoluntarydecision,morallyequivalenttoanactintheusualsense,understoodasinvolvingmuscularactivity.ForHolmes,[a]nactisalwaysavoluntarymuscularcontraction,andnothingelse:id.at91.

(38)HOLMES,supra,note32,at94.

(39)R.H.Coase,TheProblemofSocialCost,3J.L.&ECON.1,13(1960).

(40)Cf.RichardA.Epstein,AutomobileNo-FaultPlans:ASecondLookatFirstPrinciples,


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13CREIOHTONL.REV.769,775(1980).

(41)NOZICK,supra,note30,at57.

(42)Perrysupra,note30,at1549;Perry,supra,note1,at4617.

(43)CfTonyHonore,CanandCant,73MIND463(1964);TonyHonore,ResponsibilityandLuck,104L.Q.R.530,54952(1988)[hereinafterResponsibility];DANIELC.DENNETT,ELBOWROOM:THEVARIETIESOFFREEWILLWORTHWANTING(1984),ch.6.

(44)HonorResponsibility,supra,note43.Myunderstandingofoutcome-responsibilitydiffersinseveralimportantrespectsfromHonors.Seefurther,Perry,supra,note1,at488512;StephenR.Perry,Loss,Agency,andResponsibilityforOutcomes:ThreeConceptionsofCorrectiveJustice,inTORTTHEORY(KenCooper-Stephenson&ElaineGibson(eds.),1993),24,3847.

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Risk Harm and Responsibility