Social Roles and their Descriptions

1 Social Roles and their DescriptionsClaudio Masolo, Laure Vieu*, Emanuele Bottazzi, Carola Catenacci,Roberta Ferrario, Aldo Gangemi, Nicola GuarinoLaboratory for Applied Ontology, ISTC-CNR, Trento & Roma, Italy*& IRIT-CNRS, Toulouse, paper offers two main contributions. On the one hand,it establishes a general formal framework for developing afoundational ontology of socially constructed entities, in thebroadest sense of this notion; on the other hand, it furthercontributes to understanding the ontological nature of key choice here is to put all Social entities in the domainof discourse: besides Social individuals, we also consider reified Social concepts and Roles , as well as theirdescriptions, , the Social conventions or contexts thatdefine them.

2 This allows us to formally characterize in afirst-order theory the relationships among all these IntroductionNatural things like rocks, animals or trees, are normallyconsidered as inhabitants of our world. We face morehesitations with entities that appear to exist just because ofsocial conventions, , entities depending in various wayson communities of agents: these can be Social concepts likebank, money, company, president, or Social individualslike the Bank of Italy or the FIAT , it is possible to distinguish two senses ofsociality. In the first sense, mostly used in this paper, anentity is Social if it is an immaterial (more precisely, non-directly extended in space) product of a community, , ifit depends on agents who, by means of some sort ofconvention, constitute, make use of, communicate aboutand accept it.

3 In this sense, Social is roughly synonymousof conventional . In the second and stronger sense, anentity is Social , if, in addition to having a conventionalnature, its very conventional constitution involves anetwork of relations among Social agents. This network ofrelations can be interpreted (as argued in (Gilbert 1992,Searle 1990, Tuomela 1995) in different ways) in terms of(collective) intentionality, actions and deontic example, the concepts of quark and triangle can beconsidered as Social in the broader sense, since they are theresult of a conventional agreement within of thecommunities of physicists and mathematicians, while theconcept of money is also Social in the strict sense, since its definition refers to some conventionalized exchangebetween agents.

4 We will not address the peculiarities ofthis stronger sense of sociality in this paper, even thoughmost of the examples discussed here actually refer to thisrestricted Social concepts, special relevance have socialroles like catalyst, money, professor or president, asopposed to quark, bank, company or elder. Anticipating thediscussion, let s just say that Roles are concepts that can be played (in a contingent and temporary way) by certainentities, when they enter in relationships with other this paper we focus on Social Roles , in their broadersense, with two goals in mind. On the one hand, we want toestablish a general formal framework for developing afoundational ontology of Social entities.

5 On the other hand,we want to offer a further contribution to understand theontological nature of Roles and to clarify some pervadingterminology confusion. The key choice here is to put allsocial entities in the domain of discourse: besides socialindividuals, we include in our domain also reified socialconcepts and Roles (which are traditionally represented asunary predicates1) as well as the Social conventions or contexts that define them (we call the latter Descriptions ).In this way we are able to formally characterize, by meansof first-order axioms, the relationships existing among allthese entities.

6 This is indeed the main technicalcontribution of the present paper: we bind together, in thesame first-order theory, all the various entities involved inthe notion of Social structure of this paper is as follows. In section 2, wesummarize the main ontological features of Roles ,analyzing the literature in philosophy, computer scienceand linguistics. In section 3, we introduce our approach,based on a reification of concepts and Descriptions and weformalize the features of Roles individuated. In section 4,we model various relations between Roles and someproperties. In section 5, we briefly introduce the notion ofsocial individual, and discuss some interesting cases whereit is necessary to refer to (and count) individuals quaplayers of certain Roles .

7 We conclude with some reflectionson other interesting uses of our formal approach, especiallywhen we take a constructivist attitude towards ontology2. 1 Of course we may also need to reify Social relations, represented by n-ary predicates. We do not discuss this issue A preliminary axiomatization of Roles and Descriptions has beenpresented (and applied) elsewhere (Gangemi and Mika 2003) in thecontext of the so-called ontology of Descriptions and situations (D&S),whose intended coverage is wider than the theory presented here (cf. theconclusions in this paper).

8 KR 2004 2672 Understanding in the literatureThe nature of Roles and the way of representing them havebeen discussed for a long time in different knowledge representation, and more specifically inthe field of description logics, the term role is nowadayssynonymous of an arbitrary binary relation (often afunction) used to characterize the structure of a concept person , for instance, may have the role likes , which represents the relationship between a personand what she likes best. As discussed in (Guarino 1992),this was not the original KL-ONE view, however, whereroles had a more linguistic flavor, and were not supposedto stand for arbitrary relations.

9 A stricter notion of roleswas the one proposed by Sowa (1988, 2000), who assertsthat Roles are concepts, , unary predicates, althoughintimately connected to patterns of relationships .Guarino proposed a formalization of this intuition, basedon Husserl s notion of foundation, that expresses theintimate dependency between a role concept and other external concepts: there cannot be a student without atleast a subject matter , for instance. A further constraintproposed by Guarino is that Roles must be anti-rigid, are properties that are contingent (non-essential) forall their instances (Guarino and Welty 2002).

10 Acceptingthis general definition, Fan and colleagues (2001) limitroles to the representation of the extrinsic features of anentity due to its participation in an event , Roles arelinked to modalities of participation, as for the participantroles of (Davis and Barrett 2002). Loebe (2003) notesthough that Roles must not be limited to the time ofparticipation in specific events; a musician is still amusician while sleeping. He tries to characterize differentapproaches on the basis of the ontological nature of thecontexts that determine Roles , and he individuates andanalyzes in detail three kinds of role.