Pierdaniele Giaretta

An ontology of meta-level categories

We focus in this paper on some meta-level ontological distinctions among unary predicates, like those between concepts and assertional properties. Three are the main contributions of this work, mostly based on a revisitation of philosophical (and linguistic) literature in the perspective of knowledge representation. The first is a formal notion of ontological commitment, based on a modal logic endowed with mereological and topological primitives. The second is a formal account of Strawsons distinction between sortal and non-sortal predicates. Assertional properties like red belong to the latter category, while the former category is further refined by distinguishing substantial predicates (corresponding to types like person ) from non-substantial predicates (corresponding to roles like student ). The third technical contribution is definition of countability which exploits the topological notion of connection to capture the intended semantics of unary predicates.

Identity criteria and sortal concepts

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 Weltys 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.

Normative facets of risk

An explicative analysis of the concept of risk must take into account that risk assessment depends on individual beliefs and evaluations. A key point is the concept of harm, which appears to be subjective. One of the constitutive aspects of this concept is reference to values, which is also present in the statistical hypothesis testing, specifically when oriented to decision making in practical contexts. It is highlighted that some difficulties are found in specifying the ways in which the subjectivity and the values are to be taken into consideration in order to obtain a better understanding of the concept of risk. Un’analisi esplicativa del concetto di rischio deve tener conto della dipendenza della valutazione del rischio da credenze e valutazioni individuali. Un punto chiave e costituito dal concetto di danno, che sembra essere soggettivo. Uno degli aspetti costitutivi di questo concetto e il riferimento a valori che e presente anche nella verifica statistica di ipotesi, in particolare quando questa e finalizzata alla presa di decisione nei contesti pratici. Si mettono in evidenza alcune difficolta che si incontrano nello specificare i modi nei quali la soggettivita e i valori sono da prendere in considerazione allo scopo di ottenere una migliore comprensione del concetto di rischio.

A Mereology for the Change of Parts

A theory of temporal mereology is formulated in which the principles of Existence and of Uniqueness of Composition hold. The theory is consistent both with a three-dimensionalist ontology and with the change of parts, that is, with the view that at least one object has distinct parts at distinct times. Some interesting consequences of the theory joined with the change of parts, taken as an axiom, are proven. It is usually held that certain well known ontological puzzles must be solved either by adopting a four-dimensionalist ontology or by restricting some mereological principles. Here a solution to those puzzles is stated, which allows to keep all mereological principles in their generality, without adopting a four-dimensionalist ontology. The solution is achieved by denying the persistence of some of the entities involved, along the “Chrysippean” lines advocated by M. Burke and M. Rea. Although good reasons for this move are provided, some problems of the solution are also highlighted and tentatively answered.