Identity, nature and ground

The Science of the Individual: Leibniz’s Ontology of Individual Substance, 2005

Types are fundamental for conceptual domain modeling and knowledge representation in computer science. Frequently, mo- nadic types used in domain models have as their instances objects (endurants, continuants), i.e., entities persisting in time that experi- ence qualitative changes while keeping their numerical identity. In this paper, I revisit a philosophically and cognitively well-founded theory of object types and propose a system of modal logics with re- stricted quantification designed to formally characterize the distinc- tions and constraints proposed by this theory. The formal system proposed also addresses the limitations of classical (unrestricted ex- tensional) modal logics in differentiating between types that repre- sent mere properties (or attributions) ascribed to individual objects from types that carry a principle of identity for those individuals (the so-called sortal types). Finally, I also show here how this proposal can complement the theory of conceptual spaces by offering an ac- count for kind-supplied principles of cross-world identity. The ac- count addresses an important criticism posed to conceptual spaces in the literature and is in line with a number of empirical results in the literature of cognitive psychology.

Dialectica, 2005

A conception of numerical identity is introduced which, in accordance with a transcendental or imposition view of language, treats an identity predicate as having an ontologically generative function by genuinely being involved in the generation or construction of its domain of discourse. The proposed conception also allows for a plurality of identity predicates, each of which generating a domain, and it allows for the possibility that some such domains may not be unifiable with each other. All of these informal notions are explicated in formal terms. Finally, a comparison to Scott and Fourman's intuitionistic conception of identity is made. * The work presented here was funded by the Schweizerischer Nationalfonds. 2 Lauener's views on the matter have been published in Lauener 1982-1992. 3 See, in particular, Ajdukiewicz 1934. 5 A language context, or "context" in Lauener terminology, is given by delineating some frame of activity (Handlungszusammenhang) such as the development of a scientific theory. The determination of such a frame, as seen by Lauener, involves, amongst other, the choice of a language system (including, in particular, the choice of a predicate scheme, and of domains of discourse) and the description of the frame's purpose. It is, of course, unlikely that all these features of Lauenerian contexts, particularly the pragmatic ones, can be usefully represented in a formal system. This is why we have decided to focus on the constituents he calls language systems. Wolfson College, Oxford

The identity theory is meant to solve certain alleged problems with dispositional essentialism, notably that the latter struggles to characterise powers as fundamental and intrinsic properties, and also fails to make sense of the discrepancy between our understanding of properties in the manifest vs. the scientific image. However, proponents of powers still have misgivings about the identity theory. They wonder how it can deal with the apparent independent variability of qualities and dispositions, i.e. that objects with different qualities seem able to have the same powers, and the observation that one and the same power seems able to give rise to a variety of behaviours. Many enough also find that the identity theory still hasn't conceptually made sense of the identity of quality and power. Some also find it to be more of an epistemic rather than metaphysical theory. In this paper, I respond to these misgivings, arguing they are misguided.

Mind, vol. 112, 195-234, 2003.

Philosophical Studies, 1976

The concept of a kind plays a prominent role in the metaphysics associated with the Aristoteliau tradition; and at an intuitive level, what Aristotelians have meant by a kind is clear enough. Kinds are universals like man, animal, number, and color which provide us with a system for classifying objects according to what they are. 1 But while helpful as a starting point, this characterization hardly exhausts the subject of kinds. It isolates a certain classificatory role, but it does not provide us with any criteria for identifying universals which play that role. Now, I am convinced that the Aristotelian notion of a kind is a powerful tool for dealing with the problems of metaphysics; but I am also convinced that in the absence of any clear-cut criteria for applying the concept, the metaphysician's use of the notion of a kind is bound to be precarious. In this paper, I shall attempt to give substance to the traditional characterization of kinds by providing criteria of the required short. I shall not, however, provide a single set of criteria which cover all kinds. Indeed, I am inclined to think that there are no such general criteria. What I shall do is provide a set of necessary and sufficient conditions for a universal's being a lowest level kind (what Aristotle called an infima species); then, I shall point to a recursive procedure which enables us to extend the account so as to provide, for any given logical level higher than that occupied by lowest level kinds, necessary and sufficient conditions for being a kind of that level. 2 As philosophers have used the term, kinds constitute one sort of universal. They are universals to which objects belong; and in this, they differ from the properties objects are said to possess and the relations into which they are said to enter. The claim that kinds have members suggests that they are to be identified with the mathematician's classes; and the insight that kinds provide a system for classifying objects seems to confirm this hypothesis. On closer examination, however, we see that what

Acta Analytica, 2008

There is a fundamental ontological difference between two kinds of entity: things and objects. Unlike things, objects are not identical to any fusion of particulars. Unlike things, objects do not have mereological parts. While things are ontologically innocent, objects are not. Objects are meaty. I defend the distinction between things and objects, and provide an account of the nature of objects.

2021

A popular stance amongst philosophers is one according to which, in Lewis’ words, “identity is utterly simple and unproblematic”. Building from Lewis’ famous passage on the matter, we reconstruct, and then criticize, an argument to the conclusion that identities cannot be grounded. With the help of relatively uncontroversial assumption concerning identity facts, we show that not all identities are equi-fundamental, and, on the contrary, some appear to be provided potential grounding bases using two-level identity criteria. Further potential grounding bases for identities are presented. Identity might be utterly simple and unproblematic, but this is not sufficient to conclude that identities are ungrounded, or fundamental.

2005

In the paper I check approaches to identity in mathematics by Plato, Frege, and Geach against Category theory.

Logique et Analyse Louvain, 1977

There are di¤erent ways in which we might investigate and represent the successive stages of the development of our common-sense and scienti…c conceptual frameworks. Jean Piaget's "fundamental hypothesis"regarding this development is that there is a parallelism between the progress made in the logical and rational organization of knowledge and the corresponding formative psychological processes" ([9], p.13). Piaget's approach has been a general inquiry into our formative psychological processes, a type of inquiry that requires us "to take psychology seriously" (ibid., p.9). There is an alternative for philosophical logicians, however. For while it is not within our expertise to investigate formative psychological processes, we can nevertheless contribute to the study and representation of "the logical and rational organization of knowledge" through the construction of theories of logical form that are characteristic of at least some of the more important stages in the development of our common-sense and scienti…c frameworks. We adopt the methodology of such a construction in this paper where our primary concern will be the logical structure of our referential devices for quantifying, identifying and classifying things. We will be concerned in particular with how this structure is to bear upon the problem of cross-world and cross-time re-identi…cation.