In ontology the underlying nature of things is sought. Thus it is that the roles things play can sometimes be neglected. Some different sorts of things that get called roles: places in relations, ways of participating in activities, and ways of being a part of a system, are considered. Roles are then analysed from a 4-dimensional and extensional perspective. We find that in individuals a role is a state of some individual that participates in a relationship or an activity, whereas with classes it is the class itself that participate in a place in a relation. In systems (both social and functional roles) we find that roles are replaceable parts of the system that are the purpose the part plays in the whole. A 4-dimensionalist ontology of roles, linked to an upper ontology is presented, and this is used to set out the key properties of roles as found here and by others.
IOS Press, Inc.
6751 Tepper Drive
Clifton, VA 20124
Tel.: +1 703 830 6300
Fax: +1 703 830 2300 firstname.lastname@example.org
(Corporate matters and books only) IOS Press c/o Accucoms US, Inc.
For North America Sales and Customer Service
West Point Commons
Lansdale PA 19446
Tel.: +1 866 855 8967
Fax: +1 215 660 5042 email@example.com