Arguments based on Leibniz's Law seem to show that there is no room for either indefinite or contingent identity. The arguments seem to prove too much, but their conclusion is hard to resist if we want to keep Leibniz's Law. We present a novel approach to this issue, based on an appropriate modification of the notion of logical consequence.

Arguments based on Leibniz's Law seem to show that there is no room for either indefinite or contingent identity. The arguments seem to prove too much, but their conclusion is hard to resist if we want to keep Leibniz's Law. We present a novel approach to this issue, based on an appropriate modification of the notion of logical consequence.

In a series of articles, Kit Fine presents some highly compelling objections to monism, the doctrine that spatially coincident objects are identical. His objections rely on Leibniz’s Law and linguistic environments that appear to be immune to the standard charge of non-transparency and substitution failure. In this paper, I respond to Fine’s objections on behalf of the monist. Following Benjamin Schnieder, I observe that arguments from Leibniz’s Law are valid only if they involve descriptive, rather than metalinguistic, negation. Then I (...) show that the monist is justified in treating the negation in Fine’s objections as metalinguistic in nature. Along the way I make a few methodological remarks about the interaction between the study of natural language and metaphysics. I also present evidence that some of the linguistic environments which Fine relies on are, contrary to appearances, non-transparent. (shrink)

Qualifiers such as “insofar as” and “in itself” have always been important ingredients in key philosophical claims. Descartes, for instance, famously argues that insofar as he is a thinker, he is not made of matter, and Kant equally famously argues that we cannot know things in themselves. Neither of these claims is meant to be true without qualification. Descartes is not simply denying that humans consist of matter, and Kant is not simply denying that we know things. Therefore, we cannot (...) even begin to understand such claims without knowing how qualifiers work. Unlike the logic of quantification, however, the logic of qualification is rather underexplored. In this paper, I examine several instances of philosophical uses of qualifiers, taken from Aristotle, Avicenna, Descartes, Kant, and 20th c. action theory. In the light of these examples, I discuss several accounts of how such qualifiers work. (shrink)

There appear to be multifunctional artefacts of a type such that none of their functions can be attributed only to some proper part of the artefact. I use two examples of allegedly multifunctional artefacts of this kind in what follows, one due to Lynne Rudder Baker (aspirin) and another of my own (a spork). The two examples are meant to make the same point. I discuss her aspirin example, since its discussion has entered the literature, but without its being dealt (...) with satisfactorily. My example is, I believe, more intuitive than that of aspirin, which Baker introduced in her response to a challenge to her views, and so I will mostly rely on my example of a spork, especially at the end of the paper, to make my case. -/- I argue that in at least those two cases, if the standard arguments for distinguishing between an object and what constitutes it are sound, an argument showing that what we might have taken to be a single multifunctional object is in fact a case of multiple single-function artefacts which collocate. Or almost. There is one further assumption needed for these cases, beyond what the constitution cases require, and I produce reasons for accepting that assumption. (shrink)

U radu se nudi opis konteksta unutar kojeg je formuliran poznati dokaz za nužnost identiteta. Iznosi se formalni prikaz ovog dokaza kako ga je formulirao poznati filozof i logičar Saul Kripke. Također se razmatra gledište filozofa Allana Gibbarda koji nasuprot Kripkeu brani tvrdnju da neki iskazi identiteta mogu biti kontingentni. Osnovni cilj rada je upoznati domaćeg čitatelja s formalnim aspektom rasprave o nužnosti identiteta te dati kratki pregled konteksta unutar kojeg su formulirani argumenti za nužnost identiteta. In the paper, we (...) offer an overview of the context within which the well-known proof of the necessity of identity is formulated. A formal account of this proof is presented as formulated by the renowned philosopher and logician Saul Kripke. Furthermore, we discuss the account of the philosopher Allan Gibbard, who defends the claim that some statements of identity can be contingent. The main goal of the paper is to acquaint the readers who understand the Croatian language with the formal aspect of the discussion on the necessity of identity and to give a brief overview of the context within which the arguments for the necessity of identity are formulated. (shrink)

What kind of entity is a committee, a book group or a band? I argue that committees and other such social groups are concrete, composite particulars, having ordinary human beings amongst their parts. So the committee members are literally parts of the committee. This mereological view of social groups was popular several decades ago, but fell out of favour following influential objections from David-Hillel Ruben. But recent years have seen a tidal wave of work in metaphysics, including the metaphysics of (...) parts and wholes. We now have the resources to rehabilitate the mereological view of social groups. I show how this can be done, and why we should bother. (shrink)

Many philosophers accept the view that, when one object constitutes a second, the two objects can be entirely in the same place at the same time. But what of two objects such that neither constitutes the other? Can they be collocated? If there can be such a pair of objects, they would have to share the same material constituents. To show that there are two collocated objects and not just one object at a specific time and place, one has to (...) show that one of the objects has some property that the other fails to have. I claim that the properties I use in my example are legitimate substitution instances in the Law of the Indiscernibility of Identicals. I offer a metaphysically possible example that illustrates such collocation, a possible case from ‘raw nature’, two trees. (shrink)

This paper examines the logical and metaphysical consequences of denying Leibniz's Law, the principle that if t1= t2, then φ(t1) if and only if φ(t2). Recently, Caie, Goodman, and Lederman (2020) and Bacon and Russell (2019) have proposed sophisticated logical systems permitting violations of Leibniz's Law. We show that their systems conflict with widely held, attractive principles concerning the metaphysics of individuals. Only by adopting a highly revisionary picture, on which there is no finest-grained equivalence relation, can a well-motivated metaphysics (...) for rejecting Leibniz's Law be developed. We sketch one such picture—a metaphysics of stuff. Stuff ontologies can be initially motivated through ordinary language: stuff stands to mass nouns as objects stand to count nouns. The stuff ontology we propose takes stuff to be fundamental and views the world as composed of an infinite descending hierarchy of kinds and portions of stuff. We defend the coherence of this picture and offer a model theory demonstrating that it can be consistently formalized. (shrink)

The standard Leibnizian view of identity allows for substitutivity of identicals and validates transitivity of identity within classical semantics. However, in a series of works, Graham Priest argues that Leibnizian identity invalidates both principles when formalized in paraconsistent semantics. This paper aims to show the Leibnizian view of identity validates substitutivity of identicals and transitivity of identity whether the logic is classical or paraconsistent. After presenting Priest's semantics of identity, I show what a semantic expression of Leibnizian identity does amount (...) to. Then, I argue that Priest's semantic definition of identity is not Leibnizian. Finally, I offer a semantics characterization of identity in paraconsistent logic that is truly Leibnizian. I demonstrate that the correct formalization of Leibnizian identity in paraconsistent logic also validates substitutivity of identicals and transitivity of identity. (shrink)