Bratman Shared Intention

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Shared IntentionAuthor(s): Michael E. BratmanSource: Ethics, Vol. 104, No. 1 (Oct., 1993), pp. 97-113Published by: The University of Chicago PressStable URL: http://www.jstor.org/stable/2381695

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Shared Intention*MichaelE. BratmanIn Choice:TheEssential lementnHumanActionAlan Donagan arguedfortheimportanceof"will"to our sharedunderstanding f ntelligenaction.1By"will"Donagan meanta complexofcapacitiesforformingchanging, etaining,nd sometimes bandoningourchoicesand inten-tions. Choice is,forDonagan, a "determinate ariety f intending.")Our capacityto intend s to be distinguishedbothfromour capacitytobelieveand from ur capacity o be movedby desires.AndDonaganthoughtthat ntentions nvolvewhat,followingAustin,he called "'asitwere' plans."3I am broadly n agreementwiththesemain themes nDonagan'sbook, and I willprettymuch take themforgranted n whatfollows.I willsuppose that ntention s a distinctivettitude, ottobe reducedtoordinary esires ndbeliefs; hat ntentionsrecentral o oursharedunderstanding f ourselvesas intelligent gents; and that"the study

* Thanks to MargaretGilbertand Raimo Tuomela, thoughtful ommentators npresentationsof earlier,shorterversionsof thisarticle.Thanks also to Philip Clark,Rachel Cohon, Fred Dretske,David Hilbert,Henry Richardson, and Debra Satz fortheirusefulphilosophicaladvice. Barbara Herman and David Velleman providedrichandprobingcommentswhenthis rticlewaspresented ttheSeptember1992 MemorialConference n Honor of Alan Donagan, held at theUniversityfChicago. Some of theissuesthey aisedare discussedfurthernmy Shared Intention ndMutualObligation"(presented at the PacificDivisionAmericanPhilosophicalAssociation,San Francisco,March 1993). Workon thisarticlewas supported in partby the Centerfor the StudyofLanguage and Information,made possible npartthrough n awardfrom heSystemDevelopmentFoundation.1. Alan Donagan, Choice:TheEssential lementnHumanActionLondon: Routledge& Kegan Paul, 1987).2. Ibid., p. 97.3. Ibid., p. 96.4. I developed ideas thatare in some respects imilarto Donagan's themes n myIntention, lans, and PracticalReason (Cambridge, Mass.: Harvard UniversityPress,1987). Of course,thereare variousdifferencesn our views.Donagan discussesone ofthese-concerning theconsistency emands towhich ntentions re subject-in Choice,pp. 98-105. My detailed treatment f choice differs n certainwaysfromDonagan's(see Intention,lans and PracticalReason,chap. 10). And thereare otherdifferences swell. But thesedifferences re not relevanthere.Ethics104 (October 1993): 97-113X 1993byThe UniversityfChicago.Allrights eserved. 014-1704/94/0401-8731$01.00

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98 Ethics October 993ofintention" s in partthe"study fplanning."5Myhope is thatthesecommon elements in our viewsabout intention an serve as a basisfor reflection n the phenomenon of shared intention.IThat we do sometimeshave intentions hatare in an important enseshared seems clear. Wecommonly eportorexpresssuch shared ntentions by speaking of what we intend or of what we are going to do orare doing. Speaking foryou and myself might aythat we intendtopaintthe house together, o singa duet together; nd I might ay thatwe are going to New York together. n each case I report or expressa shared intention.Sometimeswe speakof the ntentions fstructuredocial groups:the Philosophy Department,for example, intendsto strengthen tsundergraduateprogram.But some shared intentions re not embed-ded in such institutional tructures. hese willbe mymain concernhere: I will focus on cases of shared intentionthat involve only apair ofagentsand do notdepend on such institutionaltructures ndauthority elations.Supposing, forexample, thatyou and I have ashared intention o paintthe house together, wantto know n whatthat shared intention onsists.6On the one hand, it is clearlynot enough fora shared intentiotopaintthehouse together hateach intends opaintthehouse. Suchcoincidentntentions o not even insurethat ach knowsofthe other'sintention r that each is appropriately ommitted o the oint activititself.On the otherhand, a shared intention s not an attitude n themind of some superagent consisting iterally fsome fusionof the twoagents. There is no single mind which is the fusion of your mindand mine.Now,one way nwhichyouand I mayarrive t a sharedintentiois to make an appropriate, explicit promise to each other. But suchpromises do not ensure a shared intention,for one or both partiesmaybe insincere nd have no intention o fulfill hepromise.Nor areexplicit promises necessaryfor shared intentions.Consider Hume'sexample of twopeople ina row boatwho rowtogether tho'theyhave

5. Donagan, Choice, . 95.6. There is a recent iteraturenartificialntelligence hatfocuseson similar ssues.See, e.g., Philip R. Cohen and Hector J. Levesque, "Teamwork,"Nous 25 (1991):487-512; Barbara J. Grosz and Candace L. Sidner, "Plans forDiscourse"; and JerrHobbs, "Artificialntelligence and Collective ntentionality: omments on Searle andon Grosz and Sidner." The latter woessaysare inIntentionsnCommunication,d. PhilipR. Cohen,JerryMorgan, and Martha E. Pollack (Cambridge, Mass.: MIT Press,1990),pp. 417-44 and pp. 445-59, respectively.


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Bratman Shared ntentionnever given promises to each other."7Such rowersmay well haveshared intention o row theboat together.

To understand hared intention, hen,we should not appealan attitude n the mindof some superagent; nor should we assuthat shared intentionsare always grounded in prior promises.conjecture s that we should, instead,understand hared intention,thebasic case, as a state ofaffairs onsistingprimarily f appropriaattitudes f each individualparticipant nd their nterrelations.8How do we determine nwhat thiscomplex ofattitudes onsisBegin witha relatedquery: What do shared intentions o, what odo theyhave in ourilives? thinkwe can identifyhreemain answeto thisquery.First, ur shared intention o painttogetherwillhelp coordinamyactivitieswithyours and yours withmine) in waysthattracktgoal of our paintingthehouse. Someone willscrapebefore,notaftthe new paint is applied by someone. Second, our shared intentiwillcoordinate our actions npartbyensuringthatmyplanningabomyrole in thehouse-painting s coordinated withyourrelevantplaning,and vice versa. If I plan to get the paint but not thebrusheswill likelycheck whetheryou plan to get the brushes. Third, oshared intentionwill tend to provide a background framework hstructures elevantbargaining.Though wesharethe ntention opaitogetherwemighthave conflictingreferences bout whoscrapesanwho paints,or about what color paint to use. Such conflicts all fbargaining in some form-not bargaining about whetherto paitogetherbut,rather,bargaining about how we are to painttogethOur shared intention, hen, performs t least threeinterrelatjobs: it helps coordinate our intentional ctions; it helps coordinaour planning; and it can structure elevantbargaining.And it doall this nwaysthattrack hegoal ofour paintingthehouse togethThus does our shared intentionhelp to organize and to unifyouintentional gency in waysto some extentanalogous to the waysiwhichthe ntentions fan individual rganizeand unify er ndividuagencyover time. An account ofwhatshared intention s should eplain how itdoes all this.

So what we want to know is this:Are thereattitudes f each othe individualagents-attitudes that have appropriate contentsan7. David Hume,A TreatisefHumanNature, d. L. A. Selby-BiggeOxford:OxforUniversity ress), p. 490. See David Lewis's remarks bout thisexample in hisConvetion:APhilosophicaltudyCambridge,Mass.: HarvardUniversityress,1969), p. 44, e.8. Let me explainwhy sayonly"primarily." claimbelow that haredintentioinvolve "commonknowledge." I do not tryhere to say what commonknowledge iBut itmaybe that t nvolves ome externalsituation n theenvironment ftheagenthatfunctions s whatLewis calls a "basisforcommonknowledge" p. 56).


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100 Ethics October993are interrelated n appropriate ways-such that the complex con-sisting f such attitudeswould,iffunctioning roperly, o the obs ofshared intention? Can we describe an appropriate complex frowhose proper functioningwould emerge the coordinated action andplanning, and the relevant framework orbargaining,characteristiof shared intention? f so, we would have reason to identifyharedintentionwiththiscomplex.IISuch an approach to shared intentionwill need to draw on an understandingof the intentions f individuals,withspecial attention o theroles of such intentions n coordination. Here I briefly ketch n ap-proach to such matters hat have developed elsewhere.9Suppose I intend now to practice the tenor part tomorrow tnoon. If all goes wellmyactivity etween now and thenwill includeall necessary preliminary teps-for example, getting hemusic if Idon't alreadyhave it-and it won't ncludeactivityncompatiblewitmy practicing hen-for example, screamingtoo much at an athletievent thenightbefore. And when tomorrow oon arrives willbe inaposition opractice; willnotbe, say, ttending movie.This normallhappens, if tdoes happen, because ofmy ntention.My intention opractice my part tomorrow oordinates my activity etween nowandthen in a waythatsupportsmy practicing t noon.How does myintentionplay thiscoordinatingrole? In part, byshaping my planningbetween now and later.Myintention opracticisan elementofa partialplan.As timegoes by need to fillnthisplanappropriately; therwisetwill uffer rommeans-end ncoherence.Somy ntentionposes relatively pecificproblems of means and preliminary stepsformy planning. I am faced, for example, with problemabout how to get a copy of the tenorpart bynoon. In contrast,myplan poses no special problem about how to get a copy of The liad,even if I would much like one. Further,myintention onstrainsmyplans in ways necessary to ensure thatmy plans remain internallconsistent nd consistentwithmybeliefs:forexample, it precludesgoingto a movie tomorrow t noon. In theseways my ntentionhelpsinsure thatmyactivities etween now and tomorrow re coordinatedwith each otherin waysthatsupport my practicing hen.For all this to workmy intention will need to have a furtheproperty. riorintentions re revocable. If thingschange in relevanways tmaybehoove me tochange my plan. Still,prior ntentionswillneed to have a certainstability.'0f we wereconstantly econsiderin

9. Primarily n my Intention, lans, and PracticalReason. See also my "What IsIntention?" n Cohen, Morgan, and Pollack,eds., pp. 15-31.10. See mydiscussion in Intention,lans, and PracticalReason, and in "Planningand the Stability f Intention,"Minds and Machines2 (1992): 1-16.


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Bratman Shared ntention 1our prior plans theywould be of littleuse. The nonreconsideratof one's prior ntentionswill typically e the default.Intentions,then, are normally stable elements of partial planThese plans are subject to demands forcoherence and consistendemandswhichhelp structure urther lanning.Such planning s nthe only mechanismthatcoordinates n individual'spurposive activover time.A tiger huntingher prey mayexhibitwonderfully oornated activitywithoutbeing capable of such planning.But forcretures ike us-as Donagan says,"creatures . . of will"-planningan important oordinatingmechanism.IIII need now to discuss two more preliminary ssues. First:my strateis to see our shared intention o J as consistingprimarily f attituof each of us and their nterrelations. t least some of these attituwill pecificallyoncernourjoiningactionofj-ing; after ll,our sharintention oJ supportscoordination specificallyn thepursuitof oJ-ing. But much talkof oint action already builds in thevery deashared intention.For us to try o solve a problem together, orexaple,we need an appropriateshared intention.We would riskcriticable circularityfour analysisof shared intention tself ppealedjoint-act-typeshat nvolved thevery dea of shared intention."2 owill want to limit ur analysansto oint-act-typeshat re,as I willsaneutral with respectto shared intention.For example, we will wato use a notion of paintingthe house togetherthatdoes not itsrequire thatthe agents have a shared intention.13 assume thatwill have available appropriate conceptionsof oint activity hataneutralwithrespectto shared intention;or anyway,mydiscussionlimitedto such cases.A second problem:theattitudes f the ndividualparticipants hare constitutive f a shared intentionwill nclude intentions f thoparticipants. ut what intendto do is toperform ctionsofmyowI cannotintendto perform he oint actionJ. So how willtheconcetion of the oint actionget into the intentions f the individuals?

Distinguishtwo strategies.First,we can appeal to myintentito play my part in ourJ-ing,where thisentails thatourJ-ing,whinotsomething strictlypeaking ntend, ssomething want. 4Secon11. The quote fromDonagan is fromChoice, . 137.12. Donagan discusses an analogous problem for ndividual ntentional ctionChoice, p. 87-88.13. Think of a case in which we paint it duringthe same time period but we aeach ignorantof the other'sactivity.14. An appeal to my ntention oplay mypart n ourJ-ing s similar othe approaof RaimoTuomela and Kaarlo Miller to whattheycall "we-intention"see "We-Intetions,"Philosophicaltudies 3 [1988]: 367-89, esp. pp. 375-76).


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102 Ethics October 993we can try o exploit the fact that we speak not onlyof intentions o,but also of intentions hat-for example, my ntention hatScottcleanup his room. Accordingly,we can speak of my ntention hatweJ.15Consider the second strategy. he idea here is not to introducesome fundamentally ew and distinctive ttitude.The attitudewe areappealing to is intention-an attitude lreadyneeded in an accountof individual ntelligent gency.But we are allowingthis attitude oinclude in itscontent the oint activity-ourJ-ing. Such appeals tomy ntention hatweJ willseem reasonablynatural given an emphasison the roles of intentionsn plans. This is because my conceptionofourJ-ingcan function n my plans in wayssimilarto myconceptionofmyownA-ing:in each case I face problemsofmeans and preliminary steps; and in each case I need to constrain he restofmyplansin the light of demands for consistency.And susceptibility o thesedemands for coherence and consistency s a characteristic ign ofintention.It mightbe objected that talkof an intention hatweJ conflictwiththeplausible idea thatone must see whatone intends s to someextent withinone's influenceor control. That is why can intendtoraise my arm but not that the sun shine tomorrow.But, in fact,thisneed be no objection to the second strategy;for that strategy anbuild an appropriate nfluence ondition nto tsunderstandingfmyintending hat weJ. It can say, roughly, hatfor me to intendthatweJ I need to see your playing your role in ourJ-ing as in some wayaffectedbyme.So the second strategy oheres withthe planning conceptionofintention and can acknowledge a plausible influencecondition. Inwhat followsI will pursue this second strategy:my account of ourshared intention oJ willappeal to yourand my ntention hat weJ.I will not tryto settlethe question of exactlywhat version of theinfluenceconditionwe should accept, for none of mymain pointsdepends on this issue. Nor will I tryto argue that the first trategmust fail.Myclaim here is onlythat the second strategys fruitful.IVI want to saywhatit is forus to intendsomethingprimarilyn termof (a) intentions nd other attitudesof each and (b) the relationsof

15. A strategy imilar to one once urged on me by PhilipCohen. In "Objects ofIntention,"Philosophicaltudies,npress)Bruce Vermazendefends ppeals to ntentionthat are not intentions o act.16. This contrastswithJohn earle'sconceptionof"we-intending"nhis "CollectivIntentionsand Actions,"in Cohen, Morgan, and Pollack, eds., pp. 401-15. A we-intention, or Searle, is a distinctive ttitude f an individual-an irreducible dditionto thekindsof attitudes fwhich we are capable. On thetack am taking,my ntentiothatweJ and my ntention o play my partin ourJ-ingare both intentions-they areboth nstancesof thesame attitude;butthey re intentions hatdiffer n their ontents


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Bratman Shared ntention 103these attitudes o each other.'7 This account should explain how it isthat shared intentions support the goal-directedcoordination ofshared activity,n part by wayof coordinatedplanningand relevantbargaining.Limiting myself o joint-act-types hat are neutralwithrespectto shared intention, proceed byconsidering seriesofviews.

VIEW 1: We intend toJ ifand only f I intend that we J andyou intend that we J.View 1 does ensure that theparticipantsn a shared intention oJ each are, in a way,committed o theirJ-ing. ut View 1 isneverthe-

less too weak.After ll, each of us can intend that we J without venknowing of the other's intentionthatweJ.'8Yet at least thatmuchcognitive inkage s involved n sharedintention.ndeed, itseemsrea-sonable to suppose that n shared intention he factthateach has therelevant ttitudess itself ut in theopen, is public. This suggests hatwe turn to:VIEW 2: We intendtoJ ifand onlyif1. I intend that weJ and you intend that weJ, and3.19 1 is common knowledge20 etweenus.21Now consideran example: you and I each intend that we go toNewYorktogether; nd this scommonknowledge.However, intendthat we go together s a result ofmykidnapping you, throwingyouinmycar, and forcingyouto oin me. The expressionof my ntention,

17. Note that my target s ourshared intention.Mydirecttarget s notwhat Tuo-mela calls a "we-intention";for a we-intention s an intentionof an individual thatconcernsa group's activitysee RaimoTuomela, "We Will Do It: An Analysis fGroup-Intentions,"Philosophynd Phenomenologicalesearch 1 [1991]: 249-77). Nor is mytargetwhat John Searle calls a "collective ntention" n his "Collective ntentionsandActions."A collective ntention, s Searle understands t, s an intention f an individualconcerninga collective's ctivity. ndeed, both Tuomela and Searle want to allow thatthere can be a we-intention/collectiventention ven if there s in factonly one individ-ual-one who falselybelieves othersare involved (see Searle, "Collective Intentionsand Actions,"pp. 406-7; and Tuomela, "We WillDo It," p. 254). In contrast,t takesat least two notonlyto tangobut even forthere to be a shared intention o tango.18. This is true even if,to intend that weJ, I must believe thatyour relevantactivity epends on mine.19. This numbering willhelp keep matters leareras we proceed.20. There is a large literature n the idea ofcommonknowledge. See, e.g., Lewis.I use here an unanalyzed notion of commonknowledge.21. View 2 is in the spirit f Raimo Tuomela's analysisof "intentionaloint goal"(see his "What Are Goals and JointGoals?" Theory nd Decision28 [1990]: 1-20, esp.p. 10). View 2 is also close to whatMargaretGilbertcalls a "strong shared personalgoal analysis"of the psychologicalbackgroundof what she calls "acting together" see"Walking Together: A Paradigmatic Social Phenomenon," Midwest tudies15 [1990]:1-14, esp. p. 3). Gilbertrejectssuch an analysis:she argues that tdoes not guaranteeappropriate obligationsand entitlements.My reasons forrejectingView 2 are quitedifferent. turnto Gilbert's oncerns ater.


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104 Ethics October 993we might ay, s theMafiasense of "we'regoingtoNew York togetheIn intending o coerce you in this way I intend to bypass your intetional agency. And that seems to rule out a shared intention o goNew York: my ntentionwill surelynot support coordinated planniabout how we are goingto getto New York. Granted, f succeedwhat I intend,our activitywill n a way be unified: we will ndeedtogether o New York. But since the way our activity s tied togetbypassesyour relevant ntentions, his s not the kindof unified gencharacteristicf shared intention.22This suggests that n shared intention not only intend thatJ; I also intend that weJ n part because of your relevant ntentiI intend hatour performance f the oint activity e inpart explainby your ntention hatwe perform he oint activity; intendthatyparticipate s an intentional gent najoint activity hat, s I know,ytoo intend.However, once we bring ntothe content fan intentiomine the efficacy f your intention, t is a shortstep to includingwell the efficacy f my wn ntention. n a case of shared intentiosee each of theparticipants,ncludingme,as participating,ntentioagents. If thisobligesme to include the efficacy fyourintentionthe content fmyrelevant ntention,hen tseemsplausibletosuppothat it also obliges me to include the efficacy f my own intentiAfter ll, I see each of us as participantsn the shared intentionthe shared activity.Why would what I intend nclude a requiremthat your intention that we J be effective, nd yet not includeanalogous requirement oncerning myown intention hatweJ?These considerations, akentogether, rgue for:

VIEW 3: We intend toJ ifand onlyif1. (a) I intend that we J and (b) you intend that weJ2. I intend thatweJ because of la and lb; you intend tweJ because of la and lb3. 1 and 2 are commonknowledgebetween us.In shared intention he constitutivententions f the individualsinterlocking, oreach agent has an intention n favorof the efficof an intention f the other. And the intentions f each involvea kiof reflexivity,oreach has an intention oncerningtheefficacyfintention fher own.Now, Donagan has argued that he choice characteristicf ndivual intentional ction is a choice thatone act in a way explainedthatverychoice: "The choices thatexplain actions are explanator

22. This example, and the one to follow afterView 3, are also discussed in"Shared CooperativeActivity," hilosophical eview101 (1992): 327-41. See esp. p332-33 (where I have more to say n defense ofconditions obe added below inVie3 and 4) and pp. 334-35 (where have moreto sayabout thekindofcoercion nvolvin the Mafiaexample).


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Bratman Shared ntention 105self-referential."23he idea that shared intention nvolvesreflexivintentions f the individuals s in a way similar n spirit o thisclaimofDonagan's. Nevertheless,myclaim about shared intention s com-patiblewiththerejectionofthe need forself-referentialityn thecaseof individualintentionalaction. In a case of shared intentioneachagent sees herselfas one of a pair of participants.Given that sheintends hattherelevant ntention ftheotherbe effective,nd givethat she recognizesthat she and the othereach have an intention nfavorof the oint activity,here s pressureon her also to intendthaher intentionbe effective.But this pressure arises fromthe socialcontext of the shared intention nd need not be present n the caseof individual,nonshared intentional ctivity. o there s roomfortheconjecture that it is onlywhen we get to shared intention hateachagent is obliged to include inwhat she intends reference o theroleof her own ntentions.To returnto the main thread, note that View 3 does notrequirethatyou and I eitherhave or aim at havinga shared conceptionofhow we are toJ. Suppose you and I each intendthat we paint thehouse together n partbecause of each ofour intentions.However, Iintendthat we paint it red all over, and you intend thatwe paint itblue all over. Allthis scommonknowledge;and neither f us iswillinto compromise.24 n View 3 we have a shared intention o paintthehouse. But this seems wrong,forneither of us is committed o theinterpersonal oordination of our relevantsubplans.Granted,forme to intend thatwe paint the house, despitemknowledgeof our differences, need to think here s some real possi-bilityhatwe willnevertheless aint t. ButperhapsI think hisbecauseI think can trickyou about the color of the paint in your can. Wemightthen satisfy -3 of View 3; and yetwe would stillnot have ashared intention. For our intentionto be shared neither of us canintend hat he other'srelevant ubplans be subverted.A shared ntention should functionto unifyour intentionalgency at least to thisextent; otherwise it would not support appropriatelycoordinatedplanning.So we need to go beyondView 3. But we also need to be carefunot to go too far. First, t would be too strongto require that thesubplans of our intentions n la and lb completelymatch,forthere

23. Donagan, Choice, . 88. Otherswho have defended imilarviews bout theselfreferential auses of intentional ction ncludeGilbertHarman, "PracticalReasoning,"ReviewofMetaphysics9 (1976): 431-63, and Change n View Cambridge, Mass.: MITPress,1986); JohnSearle, ntentionalityCambridge:CambridgeUniversityress,1983);and David Velleman,PracticalReflectionPrinceton,N.J.: PrincetonUniversity ress,1989). For a trenchant ritique of such views,see AlfredMele, "Are IntentionsSelf-Referential?" hilosophicaltudies 2 (1987): 309-29.24. Rachel Cohon helped me get thisexample into shape.


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106 Ethics October993can be features f your subplan that do notevenknowor care about,and vice versa. Perhaps your subplan includespainting n overallsorbuyingthe brushesat a certainstore.While I need to knowyou willshowup withthe brushes, may wellneitherknownorcare howyouare dressed or whereyou get thebrushes.So our subplansmaywellnot completelymatch. Still, t seems thatwe will each want theminthe end to mesh:our individualsubplans concerningourJ-ingmesjust in case there s some waywe couldJ thatwould notviolateeitherof our subplansbut would,rather, nvolvethesuccessful xecutionofthose subplans. If I intendthatwe paintsolelywithred paintand youintendthat we paint solelywithblue, our subplansdo not mesh. Butifyou intendto getthepaintatGreg'sHardware,and I simplydo notknowor care about whereyougetthepaint,thenour subplans,whiletheydo not completelymatch,maystillmesh.And it ismeshingsub-plans that are our concernin shared intention.There is a secondwayin whichwe mustbe carefulnotto go toofar.For you and I to have a shared intention oJwe need notalreadhave arrivedat subplans thatmesh. Much of our relevantplanningmay occur afterwe have arrivedat our shared intention.All thatisplausiblyrequired is that we each intendthatweJ byway ofmeshingsubplans. This leads us to:

VIEW 4: We intendtoJ if and onlyif1. (a) I intendthat weJ and (b) you intendthatweJ2. I intendthatweJ in accordance with nd because of la,lb, and meshingsubplans of la and Ib; you intend thatweJ inaccordancewith nd because of la, lb, and meshingsubplansofla and lb.3. 1 and 2 are commonknowledgebetweenus.On View 4, then, I need neitherknownor seek to knowof all yoursubplansforus to have a shared intention;nor need we alreadyhavearrived tcomplete,meshing ubplans.What srequired s that intenthatweJ bywayof meshingsubplans. I can so intend even thoughthere are as yetno specific,meshingsubplans such that intend thatweJ bywayof them.You and I maynotyethave filled n each of oursubplans, or we may have filledthem in in wayswhichdo not yetmesh.We mayhave conflicting references oncerning ubplansandbe involved n negotiations bout how to fill n our plans even whilewe have alreadystartedtoJ.It is worthreflectingn this astpoint.Our shared intention anserve as a relativelyfixed background against which relevant bar-gainingcan take place. Suppose you and I jointly ntendto paintthehouse together ut wehaveyet oagree on the colorsoron the divisionofroles. Givenour conflicting referenceswe mayengage in variousformsof bargaining.Difficultiesn such bargainingmay,of course,


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Bratman Shared ntention 107lead eitherof us to reconsiderthe intention hat we paint together.But so long as we continueso to intend,our bargainingwillconcernnot whether o painttogether uthow.Our bargainingwillbe framedbyour shared intention.Recognitionof such potentialbargainingraises a question. Sup-pose that you and I satisfy onditions1-3 of View 4 withrespecttoour going to New York togetherbut thatthereare large differencesbetweenus inrelevantbargainingpower.Perhapsit sa verymportantmatterfor you butonlya welcomebreakfromworkforme. SupposeI plan to use this difference o bargain hard formeshingsubplansthat re verymuchtomy iking.Perhaps I plan toputa lotofpressureon youtopayforbothtickets.Accordingto View4 we could stillhavea shared intention. s thatan acceptable result?I believe that it is; though, of course, too much stubbornnessmightresult n the dissolutionof our shared intention.Granted,atsome pointthe exploitationof large differencesn bargainingpowerbecomes coercive.When it does our activity f going to New Yorktogetherifthat s whatwe manage todo) willnot be a fully ooperativeactivity. ut itmaystillbe one that s ointly ntentional; nd we maystillhave a shared intention o to act.25 here stillmaybe appropriatekinds of coordination n our planningand action.A virtue fView4 is that t allowsfor haredintention venwhenthe agentshave different easons forparticipating.We can intendtosingtheduet together ven thoughmyreason is the ove ofthe musicand yours s, instead,the chance to impressthe audience.View4 does have a drawback: t does notyetprovidefor sharedintention o playa competitivegame together.You and I mighthavea shared intention o playchess together nd yetneitherofus intendthat our subplansmesh all thewaydown. After ll, I intendto try oscuttleyour plans forcheckmatingme. I thinksuch cases will forcemodestmodificationsn View 4; but I will not try o get thisstraighthere. Instead, I wantto explorefurtherwhether, ases ofcompetitivegames to one side, View 4 providesforappropriate explanationsofthecoordinatedplanningand action,and associatedbargaining, har-acteristic f shared intention.VBegin byreflectingn three basic points.First, hared intention, s Iunderstand t, s not an attitude n any mind. It is not an attitude nthe mindof some fusedagent,for there s no suchmind;and it s notan attituden the mindor mindsof eitherorbothparticipants.Rather,it s a stateof affairs hatconsistsprimarilynattitudesnone ofwhich

25. For suggestions f other conditions n cooperativeactivityhat re not nsuredbythesuccessful xecutionof a sharedintention, ee my"Shared CooperativeActivity."


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108 Ethics October993are themselves heshared intention) ftheparticipants nd interrela-tionsbetweenthose attitudes.Second, to sayinwhatshared intention onsists have sought tocombinetwomain elements: 1) a generaltreatment ftheintentionsof individuals nd (2) an account of the special contentsof the inten-tions of the individualparticipants n a shared intention. ntentionsof individuals re normally tableelements n larger,partialplans ofthose individuals.These plans are subjectto demandsformeans-endcoherenceand consistency. ecause of thesedemands, ntentions endtopose problemsforfurther racticalreasoningand toconstrain olu-tions to those problems. Given these featuresof the intentionsofindividuals, nd giventhespecialcontents dentified nView4, I wantto explain how that in which a shared intentionconsistssupportscoordinatedplanningand action,and appropriatebargaining,n pur-suitof thejoint activity.Shared intentionconsistsprimarily f a web of attitudes f theindividualparticipants.These attitudes f the individuals re subjecttovariousrationalpressures. n particular, heintentions ftheparti-cipants are subject to demands forconsistency nd coherence. Thespecific mpactof these demandswilldepend, of course, on the con-tentsof these intentions.And in shared intention herelevant nten-tionsof the individualparticipantshave the special contentswe havebeen discussing. So-and this is the thirdpoint-what we want toshow s that ntentions f ndividualswith hesespecialcontents houldlead to planning,bargaining, and action of those individualswhich,taken together,constituteappropriatelycoordinated planning andunifiedshared activity. he unified actionand coordinatedplanningcharacteristic fshared ntention s tobe explainedprimarilyyappealto the functioningof the attitudeswhich are constituentsof theshared intention.Let us see how steps n thedirection f View 4 contribute o suchan explanation. Begin withView 2. Condition 1 of View 2 requiresthat each intendsthatweJ. So thedemand formeans-endcoherenceof the plans of each insuresrationalpressureon each participant opursue means to the ointJ-ing. t also follows,giventhedemand forconsistency f each agent's plans, that there is rational pressure oneach to eschew courses of action believed byher to be incompatiblewiththe ointJ-ing.So far so good. But whatwe learnfrom heMafiacase is thatthisdoes not insurethat there s rationalpressureon each participant oaim at coordinationwiththe other'ssuccessful xecutionof her nten-tion.Yet thepursuitofcoordinationwith heother's uccessful xecu-tionof her relevant ntention s essential to the kind of coordinatedplanningcharacteristic f shared intention.


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Bratman Shared ntention 109This bringsus to View3. The conditions f View3 insure rationapressure on each participant o seek means not onlyto the ointJ-in

but also to the joint J-ingby way of the other's intention. Now, Ifrequently orm myintentions n the light of myexpectations boutyour intentionsand actions, including expectationsabout how mintentionswill nfluenceyours. Since my expectations bout how myintentionswill nfluenceyours may depend on myexpectations bouthow you expect my intentionsto be influencedby yours, this canget quite complex. But in this, s Schelling says,"spiralof reciprocaexpectations,"we still each see the other's ntentionsmerelyas dataforour deliberations, lbeit as data that re potentiallyffected y ourown decisions.26n contrast, gentswho satisfyhe conditions ited nView 3 do not see each other's relevant ntentionmerely s a datum,foreach intends hat the oint activity o in partby wayof theefficacof the other's intention. Each is rationallycommitted to pursuinmeans, and eschewingobstacles,to the complex goal of theirJ-ing ywayof the otheragent'srelevant ntention.Each aims at the efficacof the intention f the other.

In requiring hatthe participants' ntentionsnterlocknthisway,View 3 gives up on the dea, implicitnView2, thatthecrucial inkagebetweentheattitudes f those who share an intention s merely ognitive.27 ppropriatecommonknowledge,or thelike, s nota sufficielink for shared intention.Each agent needs also to embrace as herown end the efficacy f the other's relevant ntention.However, the conditionsof View 3 still do not insure that eachagent aims at therebeing meshing subplans. The conditions f View3 do insure that each agent seeks a consistent ndividualplan in sup-port of a joint J-ing in which each agent's intention that theyJ isefficacious. ut these conditionsdo notinsure thateach agent intendthat the subplans of both,takentogether,be jointlyconsistent: hais the lesson of the paintingcase. But shared intention hould brinwith t rationalpressurein the directionof subplans of bothparticipantsthat re, takentogether,ointlyconsistent. y requiring hattheparticipants ntendthattheyJ by wayof meshing subplans,View 4insuressuch rationalpressure.Finally,View 4 makes it clear whyshared intentionswill some-timesframerelevantbargaining.On View 4 each agent aims at aperformance f the oint J-ingthatgoes by wayof each participant'relevantntention nd itsmeshing ubplans.So eveniftheparticipant

26. Thomas Schelling,TheStrategyfConflictCambridge,Mass.: Harvard Univer-sityPress, 1960), p. 87.27. Gilbert n "WalkingTogether,"and Searle in "Collective ntentions" lso rejectrelated ideas, thoughfor different easons.


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110 Ethics October993have differing references bouthowthey re toJ,neitherparticipantwillbe in a position to pursue such preferences n waysthatbypasstheother's ntentions/subplans.his makes it ikely hat n such casesthedemandon each agent thather plans be means-endcoherentwilllead to rationalpressure n thedirection fbargainingthat s framedby the shared intention.Suppose, then, thattheintentions findividualparticipants avethecontents nd interrelationsited nView4; and suppose thattheseintentions-like intentions enerally-are subjecttodemandsfor on-sistency nd means-endcoherence.These rationalpressureson theseintentions f those individualswill issue in pressurein the directionof coordinatedplanning and action,and appropriatebargaining,di-rectedat the oint actionofJ-ing.And that s whatI wanted to show.VIMargaretGilberthas argued that in an important ense of "actingtogether" ach participanthas associated nonconditionalobligationstoactand nonconditional ntitlementsorebuke theotherforfailuresto act.28On View 4, ifyou and I have a shared intention oJ thenyou ought to performyour role if you continueto intendthat weJ.But View 4 by itself eems to offerno guaranteethatby virtueofourhaving a shared intentionyou have a nonconditionalobligationtoperform.Does thissuggest thatsomething s missing n View 4?Recall thatintentions re subject to a demand forstability. nereason for this is that the reconsiderationof an intentionalreadyformedcan itselfhave significantosts; a second is thatan agent whotoo easilyreconsidersherprior ntentionswillbe a lessreliablepartnerin social coordination.This latter, ocial pressure towardstability sparticularly elevant to the stability f intentionsconstitutive f ashared intention.So our approach to shared intentioncan accountforrationalpressureon a participatinggent not too easilytoabandonher relevant ntentions.Note further hat if each agent's relevantintentions re fairlystable itwillnormallybe reasonable foreach to relyon the othertostickwith the oint project.The stability f theconstituentntentionsthereby upports each in planningon thecontributions f the other,just as we would wantin coordinatedplanning.When I too easily abandon my intentionthat we take a walktogether am, then,being unreasonable. But it does not followthatinabandoningmy ntention am violating nonconditional bligationtoyou, a nonconditional bligationgrounded n our sharedintention.To be sure, shared intentions re frequently ccompanied by such

28. For example, pp. 5-6 of "WalkingTogether."This summarizes spects of hermuch longer discussion n On SocialFacts London: Routledge, 1989).


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Bratman Shared ntention 111obligations. In arrivingat a shared intentionwe frequentlymakepromisesor reachagreementswhichgeneratecorrespondingnoncon-ditionalobligations.Further, nce we beginexecutinga sharedintentionimplicitpromisesfrequentlyrise-promises thatgeneratenon-conditionalobligations.Still, such a promise or agreementdoes notseem to be, strictlypeaking,necessaryfora shared intention.Imagine twosingerswhoeach highlyvalue theirduet-singing utneverthelesshave a clear understanding etweenthemthatneither smakinganybindingpromiseto or agreementwith heotherconcern-ing theirsinging.Each publiclystatesthatshe reservesthe right tochange her mind.These two could stillshare an intention o sing aduettogether.29heycould still ngage incoordinatedplanning imedat their ingingthe duet and inwhicheach relies on theparticipatioof theother.Granted,thenormalcase ofsharedintentionwill notbelikethis. n a normalcase there will ikelybe some promise or agree-ment; and that willfurther ontribute o the confidenceof each thatshe can plan on the participation f the other.Nevertheless, uch apromise or agreementdoes not seem essentialto shared intentionAnd when there is no such promise or agreement,or some otherobligation-generating rocess,the shared intentionmaynot imposea nonconditionalobligationto stickwiththe oint action.Considertwodifferent esponses to this.First, ne mighttry oinsistthat the mere satisfaction f the conditions of View 4, in theabsence of some further bligation-generatinggreement,does notensure shared intention.30 o our singers do not in fact have ashared intention.At thispointperhaps thedisputeismerelyverbaland we shouldsimply peak of shared intention n a weakerand in a stronger ense.The weakersense is captured,prettymuch,by View 4. The strongesense involvesyeta further ondition, hatthere be a bindingagree-ment.3" have argued thatshared intention n the supposed weakersense supports coordinated planning and action, and relevantbar-

29. Lewis makes a similarpoint (p. 34).30. This is roughly n the spirit f some ofGilbert'sremarks s commentator nan earlierand shorterversionof thisarticleat the CentralDivision of the AmericanPhilosophicalAssociation APA), Louisville,Ky. (April 1992). (Gilbertput thepoint ntermsof a special notion of joint commitment,"ndicating hat"itmaybe reasonableenough to thinkof [joint commitment] s an 'implicit greement'.") This was alsoRaimo Tuomela's tack in his replies as commentator n an earliershorterversionofthisarticle presented at the meetingsof the SocietyforPhilosophy and Psychology,Montreal,June 1992).31. In her commentsat the Central Division of the APA, Gilbertsuggested (asPaul Weirichbroughtout in thediscussionperiod) that ucha binding greement, ndtheresulting bligations nd entitlements, ould itself e sufficientor shared inten-tion. But that eems to mewrong, incebinding greementsdo notguarantee ntentionson the partof the individualagents to act accordingly.That is why understand he


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112 Ethics October993gaining, aimed at the joint activity nd that it is typically ut notnecessarily ccompanied by relevantnonconditional bligations.Thatseems to me a reason to see the phenomenon captured byView 4 asat the heart of thematter.At the least we have seen that there s animportantkind of shared intentionthatdoes not essentiallynvolvesuch obligations. Such shared intention s primarily psychologi-cal-rather than primarily normative-phenomenon. The step tononconditional bligations nd entitlementss a stepbeyondthismorebasic phenomenon.Consider a second response tomydefense ofView 4. One mighturge that a shared intention n the sense of View 4 could only comeabout by way of a process of a sort that generates correspondingnonconditionalobligations.Perhaps the process is not,strictlypeak-ing, one of agreement or the exchange of promises;itmay ust be amoregeneralkindofmutual assurance. But thisprocesswillneverthe-less be sufficiento supportcorresponding bligations.My replyto this is twofold.First,the main claim-that sharedintentionmust lways come about by way of an obligation-generatinprocess-does notseem to me veryplausible: thecase ofthecautioussingerswhodisavowobligation eemsa fairly learcounterexample.32But, second, even if I were wrong about this,thisneed not be anobjectiontoView 4. We could still llow thatView4 sayswhatsharedintentions, whilenotingthatthe creationofa sharedintention ringswith tcertainnormative onsequences. We could still greewithView4 that hared ntention onsistsprimarilyfa web of ndividualpsycho-logical states and their nterrelations.t would ust turnout thatthecreation of thispsychologicalweb has normative onsequences.VIIThis approach to shared intention sbroadly ndividualisticn spirit.3Granted,much recent work in the philosophyof mindhas arguedthatour ordinarywaysofspecifyinghe contents f theattitudes rawon featuresoutsideof the individual whose attitudes re in question.stronger ense of shared intention, fsuch therebe, to include the conditions itedinView 4 as well as a further onditionspecifying n appropriate normative relationbetweenthe participants.32. I believe that certain cases of coerced shared intentionwould also providecounterexamplesto thisoverly general claim. Other potentialcounterexamplesmaycome fromcases of shared intention n whichthe commonknowledge s grounded nthebackgroundknowledgeof the participants nd is not theresultof assurances eachgives the other (a point David Velleman helped me see-though he did this whiletrying o convince me that such cases posed problems forView 4). I discuss thesemattersfurthern my"Shared Intentionand Mutual Obligation."33. Assuming that the common knowledge condition can be understoodalongindividualisticines.


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Bratman Shared ntention 113Such externalfeaturesmay include the causal contextof the use ofnames or naturalkindterms,34s well as relevant inguistic racticesofthecommunitynwhichtheindividual s located.35 he individual-ismofmyapproach tosharedintention an grant hese nsights boutwhatdetermines hecontentof an individual's ttitudes. he claimisnot thatwe can specify hese contents n waysthatdo not appeal toelementsoutside the individualwhose attitudes re in question. Theclaim,rather, s that shared intentionconsistsprimarily f attitudesof individuals nd their nterrelations. he coordinatedplanningandaction,and framework orbargaining,characteristic f shared inten-tion emerge fromthe proper functioning f these attitudesof theindividualparticipants.

34. HilaryPutnam,"The Meaning of Meaning',"inhisMind,Language ndReality(Cambridge: Cambridge University ress, 1975), vol. 2.35. Tyler Burge, "Individualism

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Bratman Shared Intention

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