Identity criteria and sortal concepts

• Authors: Massimiliano Carrara;Pierdaniele Giaretta
• Venue: Proceedings of the international conference on Formal Ontology in Information Systems - Volume 2001
• Year: 2001

In this paper we focus on a specific aspect of the notion ofconceptualisation, i.e. on the issue of the specification ofa certain kind of concept: sortal concept. Our startingpoint is the intuitive idea that a sortal concept cannot bespecified in isolation from a general notion of entity. We thinkthat this idea has some bearing on the way in which identitycriteria should be conceived, since they are usually taken as afundamental tool for the specification of a sortal concept. Thefirst goal of our paper is to discuss and point out somedifficulties concerning the relation between sortals and identitycriteria. In general, we think that the specification of a sortalpresupposes - in Russellian terms - a range of significance onwhich the concept is defined. It follows that the sortal cannot bestated without a specification of its range of significance. Thismeans that identity criteria for a sortal K providingconditions of identity only for objects falling under K arenot enough to specify K. Independently of this point, we arequite skeptical about the possibility of achieving a formalsatisfactory definition of sortal. We will try to show thateven Guarino and Welty's last proposal [4] does not succeed. Oursecond goal concerns which concepts are to be taken as sortals. Bythinking that identity criteria are necessary and sufficientconditions for identity, Guarino and Welty cannot accept that, say,a is S1 and a is S2, in thecase that S1 and S2 are associated withincompatible criteria. So they are lead to postulate, for example,that not a but b is S2 and a isconstituted by b. We defend the thesis that it is possibleto take some concepts - in our case S2 - as endowed onlywith necessary conditions for identity. We will argue for somespecific choices.