Object perception deploys a suite of perceptual capacities that constrains attention, guides reidentification, subserves recognition, and anchors demonstrative thought. Objects for perception—perceptual objects—are the targets of such capacities. Characterizing perceptual objects for multisensory perception faces two puzzles. First is the diversity of objects across sensory modalities. Second is the unity of multisensory perceptual objects. This paper resolves the puzzles. Objects for perception are structured mereologically complex individuals. Perceptual objects are items that bear perceptible features and have perceptible parts arranged to (...) form a unified whole. This circumscribes the targets of object perception where neutral talk concerning intentional objects and objects of perception cannot. Nonetheless, it is more permissive than identifying perceptual objects with material bodies, which excludes too much and leans too heavily on vision. The account thus is tailored to capture the role of objects in perception beyond vision: tactual, auditory, and olfactory objects are individuals with differing structures. Its flexibility also enables the account to accommodate shared objects for multisensory perception: multisensory perceptual objects are mereologically complex individuals with hybrid structure. For instance, one can bimodally perceive a common whole with parts accessible to one but not both modalities. Each sense provides a partial perspective on a complex whole that is perceptible through the coordinated use of multiple senses. Understanding perceptual objects as structured mereologically complex individuals thus provides a theoretically useful notion of an object for multisensory perception that resolves the puzzles of diversity and of unity. (shrink)

The standard argument for the existence of distinctively mathematical objects like numbers has two main premises: some mathematical claims are true, and the truth of those claims requires the existence of distinctively mathematical objects. Most nominalists deny. Those who deny typically reject Quine’s criterion of ontological commitment. I target a different assumption in a standard type of semantic argument for. Benacerraf’s semantic argument, for example, relies on the claim that two sentences, one about numbers and the other about cities, have (...) the same grammatical form. He makes this claim on the grounds that the two sentences are superficially similar. I argue that these grounds are not sufficient. Other sentences with the same superficial form appear to have different grammatical forms. I offer two plausible interpretations of Benacerraf’s number sentence that make use of plural quantification. These interpretations appear not to incur ontological commitments to distinctively mathematical objects, even assuming Quine’s criterion. Such interpretations open a new, plural strategy for the mathematical nominalist. (shrink)

This paper discusses the principle of recombination for possible worlds. It argues that arguments against unrestricted recombination offered by Forrest and Armstrong and by David Lewis fail, but a related argument is a challenge, and recommends that we accept an unrestricted principle of recombination and the conclusion that possible worlds form a proper class.

The surviving sources on the Stoic theory of division reveal that the Stoics, particularly Chrysippus, believed that bodies, places and times were such that all of their parts themselves had proper parts. That is, bodies, places and times were composed of gunk. This realisation helps solve some long-standing puzzles about the Stoic theory of mixture and the Stoic attitude to the present.

David Lewis’s arguments against magical ersatzism are notoriously puzzling. Untangling different strands in those arguments is useful for bringing out what he thought was wrong with not just one style of theory about possible worlds, but with much of the contemporary metaphysics of abstract objects. After setting out what I take Lewis’s arguments to be and how best to resist them, I consider the application of those arguments to general theories of properties and relations. The constraints Lewis motivates turn out (...) to yield an argument for concretism about possible individuals that is quite different from the better-known Lewisian arguments for that position. The discussion also touches on the puzzling question of whether things are the way they are because of the properties they have, or are the properties and relations the way they are because of the things that have them. (shrink)

The question of what truths are necessary in the broadest possible sense is a difficult one to answer, as is the question of what the limits are to what is possible. (Most people would see these two questions as different sides of the same coin, of course, since many think the question of what is possible is just the question of what is not necessarily ruled out). We have three general sorts of strategies for determining whether something is necessary (or (...) possible). We can identify it in a class that we were previously sure was a class of things that are necessary – we might show it is a theorem of a logical system that we have confidence in, or that the sentence appears to be true simply in virtue of the meanings of the words, or that it is a true statement involving names or about natural kinds of the “necessary a posteriori” sort discussed by Kripke and Putnam, and there are perhaps other classes of claims which we are prepared to accept are necessary if true.1 Likewise, we might establish the possibility of something occurring by reference to a class of well-established or uncontroversial possibilities: e.g. we are inclined to think that it is possible (in the broadest sense) for an event to occur in the future if one of the same kind has occurred in the past. (shrink)

A dilemma put forward by Schein (1993) and Rayo (2002) suggests that, in order to characterize the semantics of plurals, we should not use predicate logic, but plural logic, a formal language whose terms may refer to several things at once. We show that a similar dilemma applies to mass nouns. If we use predicate logic and sets when characterizing their semantics, we arrive at a Russellian paradox. And if we use predicate logic and mereoogical ums, the semantics turns out (...) to be too weak. We then develop an account where mass nouns are treated as non-singular terms. This semantics is faithful to the intuition that, if there are eight pieces of silverware on a table, the speaker refers to eight things at once when he says: "The silverware that is on the table comes from Italy." We show that this account provides a satisfactory semantics for a wide range of sentences. (shrink)

A dilemma put forward by Schein (1993) and Rayo (2002) suggests that, in order to characterize the semantics of plurals, we should not use predicate logic, but non-singular logic, a formal language whose terms may refer to several things at once. We show that a similar dilemma applies to mass nouns. If we use predicate logic and sets, we arrive at a Russellian paradox when characterizing the semantics of mass nouns. Likewise, a semantics of mass nouns based upon predicate logic (...) and mereological sums is too weak, since it cannot characterize the “intermediary” construals that sentences containing mass nouns may receive. We then develop an account where mass nouns are treated as non-singular terms, which may refer to several things at once. This semantics is faithful to the intuition that, if there are eight pieces of silverware on a table, the speaker refers to eight things at once when he says: “The silverware that is on the table comes from Italy”. We show that this account provides a satisfactory semantics for a wide range of sentences, including cases often seen as difficult, like “The gold on the table weighs seven ounces” (Bunt 1985) and “All phosphorus is either red or black” (Roeper 1983). (shrink)

Necessitism is the controversial thesis that necessarily everything is necessarily something, namely that everything, everywhere, necessarily exists. What is controversial about necessitism is that, at its core, it claims that things could not have failed to exist, while we have a pre-theoretical intuition that not everything necessarily exists. Contingentism, in accordance with common sense, denies necessitism: it claims that some things could have failed to exist. Timothy Williamson is a necessitist and claims that David Lewis is a necessitist too. The (...) paper argues that, granted the assumptions that lead to interpret the Lewisian as a necessitist, she can preserve contingentist intuitions, by genuinely agreeing with the folk that existence is contingent. This is not just the uncontroversial claim that the Lewisian, as a result of the prevalence of restricted quantification in counterpart theoretic regimentations of natural language, can agree with the folk while disagreeing with them in the metaphysical room. Rather, this is the claim that it is in the metaphysical room that the Lewisian can endorse the intuitions lying behind contingentism. (shrink)

Ontology is the philosophical discipline which aims to understand how things in the world are divided into categories and how these categories are related together. This is exactly what information scientists aim for in creating structured, automated representations, called 'ontologies,' for managing information in fields such as science, government, industry, and healthcare. Currently, these systems are designed in a variety of different ways, so they cannot share data with one another. They are often idiosyncratically structured, accessible only to those who (...) created them, and unable to serve as inputs for automated reasoning. This volume shows, in a nontechnical way and using examples from medicine and biology, how the rigorous application of theories and insights from philosophical ontology can improve the ontologies upon which information management depends. (shrink)

Humeans take reality to be devoid of ‘necessary connections’: things just happen. Laws of nature are to be understood in terms of what ‘just happens’, not vice versa. Here the Humean needs some conception of what it is that ‘just happens’ – a conception of the Humean mosaic. Lewis’s Humeanism incorporates such a conception in the form of a Lewis-style metaphysics of objects, properties, and modality. Newer versions of Humeanism about laws of nature, such as the Better Best Systems approach, (...) typically reject such a Lewisian metaphysics, but it remains unclear what they can offer in its place. By exploring different candidate conceptions, this paper sheds light on the limits of Humeanism about laws of nature: not all conceptions of the Humean mosaic form a suitable basis for a Humean theory of laws. In fact, only a metaphysics roughly in line with Lewis’s will do. The paper ends with a tentative generalization of this result, thus pointing to the ‘limit’ of Humeanism in general: taking the Humean way of thinking to its limit results in a rejection of the whole idea of such a mosaic – and hence of Humean mosaic-based accounts of anything. (shrink)

Frege taught us how to understand one form of predication: an atemporal one. There is also a different, temporal form of predication, which I briefly introduce. Accordingly, there are two fundamentally different approaches to time: a reductive one, aiming to account for time in terms of Frege’s atemporal predication, and a non-reductive one, insisting that the temporal form of predication is sui generis, and that time is to be understood in its terms. I do not directly argue for or against (...) reductionism in this paper. Rather, by evaluating the debates on endurantism–perdurantism, A-theory–B-theory, and presentism–eternalism, I argue that these debates, although aiming to be fundamental, largely boil down to mere quarrels between alternative reductive approaches. We should take notice of this fact and reorient ourselves within the debate on time accordingly: the real issue is whether we should reduce or not. I briefly sketch in what sense endurantism, A-theory, and presentism may be developed on a properly anti-reductionist basis. (shrink)

It is often claimed that principles of individuation imply essential properties of the things individuated. For example, sets are individuated by their members, hence sets have their members essentially. But how does this inference work? First I discuss the form of such inferences, and conclude that the essentialist inference is not a purely formal matter: although there is a form which all principles of individuation have in common, it is not true that any statement of that form is a principle (...) of individuation, and hence there is no valid inference based purely on that form. However, I argue that there is a viable version of the essentialist inference nonetheless. The resources for a proper reconstruction of this type of inference can be gathered from reflections upon the role principles of individuation play in the project of the ontologist: such principles turn out to carry a modal weight similar to that of definitions or conceptual truths. It follows that, no matter how austere the ontology, some portion of essentialist modality is inevitable. (shrink)

After a critical presentation of the debate between absolutists and relativists regarding generality where I show that the debate is framed in a way that is bound to be harmful to the relativist’s position, I examine critically one of the customary arguments advanced against the relativist: the expressibility objection (according to which the relativist would be logically unable to express her own position). I then propose a radical way out of this debate-usually centered on semantic paradoxes-by arguing that it rests (...) on an unintelligible notion of “object”. I finally introduce a useful distinction between omnis and totus to elucidate the notions in play. (shrink)

The aim of this paper is to elucidate the mereological structure of complex states of affairs without relying on the problematic notion of structural universals. For this task tools from graph theory, lattice theory, and the theory of relational systems are employed. Our starting point is the mereology of similarity structures. Since similarity structures are structured sets, their mereology can be considered as a generalization of the mereology of sets..

For some time now, Jaegwon Kim has argued that irreducible mental properties face the threat of causal inefficacy. The primary weapon he deploys to sustain this charge is the supervenience/exclusion argument. This argument, in a nutshell, states that any mental property that irreducibly supervenes on a physical property is excluded from causal efficacy because the underlying physical property takes care of all of the causal work itself. Originally intended for mental properties alone, it did not take long for his critics (...) to suggest the argument generalizes across all of the special science properties as well. Kim responds in two different ways to the generalization problem. The first response, which I call the higher-level solution, is ably dismissed by numerous critics. The second response, which I call the identity solution, has not faced comparable scrutiny. In this paper I argue that the identity solution faces numerous problems of its own. (shrink)

In this paper I develop a version of universalism that is non-mereological. Broadly speaking, non-mereological universalism is the thesis that for any arbitrary set of objects and times, there is a persisting object which, at each of those times, will be constituted by those of the objects that exist at that time. I consider two general versions of non-mereological universalism, one which takes basic simples to be enduring objects, and the other which takes simples to be instantaneous objects. This yields (...) three versions of endurantism, of which I ultimately defend the version I call universalist endurantism. Universalist endurantism is the thesis that (i) for any arbitrary set S of instantaneous simples that exist at the same instant, there exists a fusion of the members of S, and (ii) for any arbitrary set S* of instantaneous fusions each of which exist at a different instant, there exists an enduring object O that is constituted by those fusions at those instants. Universalist endurantism is ‘non-mereological’ in that the relation that holds between instantaneous fusions and persisting objects is not the part/whole relation, but rather, is the relation of constitution, thus allowing that the persisting objects are three rather than four dimensional. I argue that universalist endurantism not only has the various benefits of mereological universalism in allowing vagueness to be explicated as semantic indeterminacy, but in addition allows the endurantist to hold that some properties are genuinely intrinsic and are exemplified simpliciter. (shrink)

Here is a common view. There exist things, and there exists stuff, where roughly, ‘thing’ is a count noun, and ‘stuff’ is a mass noun. Syntactically, ‘thing’ functions as a singular referring term that takes ‘a’ and ‘every’ and is subject to pluralisation, while ‘stuff’ functions as a plural referring term that takes ‘some’ and is not subject to pluralisation. Hence there exists a thing, and some stuff. Usual versions of the common view endorse two principles about portions of stuff. (...) The first principle is that (temporal) mereological essentialism is true of portions (parcels, masses, quantities) of stuff, where mereological essentialism is the thesis that for any persisting object or portion of stuff, that object or stuff has the same parts at every time at which it exists. The second principle is that portions of stuff obey a principle of stuff composition: for any two portions of stuff P1 and P2, there exists a portion of stuff that is the fusion of P1 and P2. I argue that these two principles are inconsistent. In particular, since I am sympathetic to PSC, I argue that mereological essentialism is false of portions of stuff. (shrink)

There is a general form of an argument which I call the ‘argument from vagueness’ which attempts to show that objects persist by perduring, via the claim that vagueness is never ontological in nature and thus that composition is unrestricted. I argue that even if we grant that vagueness is always the result of semantic indeterminacy rather than ontological vagueness, and thus also grant that composition is unrestricted, it does not follow that objects persist by perduring. Unrestricted mereological composition lacks (...) the power to ensure that there exist instantaneous objects that wholly overlap persisting objects at times, and thus lacks the power to ensure that there exists anything that could be called a temporal part. Even if we grant that such instantaneous objects exist, however, I argue that it does not follow that objects perdure. To show this I briefly outline a coherent version of three dimensionalism that grants just such an assumption. Thus considerations pertaining to the nature of vagueness need not lead us inevitably to accept perdurantism. (shrink)

Hybrid languages are introduced in order to evaluate the strength of “minimal” mereologies with relatively strong frame definability properties. Appealing to a robust form of nominalism, I claim that one investigated language \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathcal {H}_{\textsf {m}}$\end{document} is maximally acceptable for nominalistic mereology. In an extension \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathcal {H}_{\textsf {gem}}$\end{document} of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathcal {H}_{\textsf {m}}$\end{document}, a modal analog (...) for the classical systems of Leonard and Goodman and Leśniewski is introduced and shown to be complete with respect to 0-deleted Boolean algebras. We characterize the formulas of first-order logic invariant for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathcal {H}_{\textsf {gem}}$\end{document}-bisimulations. (shrink)

This paper defends three theses: that presentism is either trivial or untenable; that the debate between tensed and tenseless theories of time is not about the status of presentism; and that there is no temporal analogue of the modal thesis of actualism.

A serious flaw in Hartry Field’s instrumental account of applied mathematics, namely that Field must overestimate the extent to which many of the structures of our mathematical theories are reflected in the physical world, underlies much of the criticism of this account. After reviewing some of this criticism, I illustrate through an examination of the prospects for extending Field’s account to classical equilibrium statistical mechanics how this flaw will prevent any significant extension of this account beyond field theories. I note (...) in the conclusion that this diagnosis of Field’s program also points the way to modifications that may work. (shrink)

This paper aims to motivate a new beginning in metaphysical thinking about persistence by drawing attention to the disappearance of change in current accounts of persistence. I defend the claim that the debate is stuck in a dilemma which results from neglecting the constructive role of change for persistence. Neither of the two main competing views, perdurantism and endurantism, captures the idea of persistence as an identity through time. I identify the fundamental ontological reasons for this, namely the shared commitment (...) to what I call ‘thing ontology’: an ontology that gives the ontological priority to static things. I conclude by briefly indicating how switching to a process ontological framework that takes process and change to be ontologically primary may allow for overcoming the dilemma of persistence. (shrink)

This paper is concerned with what I call the ‘problem of unity’ . This is the puzzle of how Armstrong‐like states of affairs are unified. The general approach is ‘relational internalism’: the unifier of such a state of affairs is a relation of some sort in it. A view commonly associated with relational internalism is that if such a relation satisfies a certain ‘naive’ expectation to a relation – that it is related to its relata – then Bradley's regress results. (...) As I argue, for one very natural species of relational internalism, this is indeed the case. Influential writers on the topic have therefore maintained that this relation is not related to its relata. But, as we shall see, while this ‘classic’ relational internalism obviously avoids Bradley's regress, intuitively, it fails completely to solve the problem of unity. I argue, however, that given the rejection of a natural, but unfounded, assumption of conventional relational internalism, a unique relation can unify states of affairs without leading to Bradley's regress. I consequently propose a novel version of relational internalism on which states of affairs are unified by such an entity. (shrink)

Anyone who admits the existence of composite objects allows a certain kind of coincidence, coincidence of a thing with its parts. I argue here that a similar sort of coincidence, coincidence of a thing with the stuff that constitutes it, should be equally acceptable. Acknowledgement of this is enough to solve the traditional problem of the coincidence of a statue and the clay or bronze it is made of. In support of this, I offer some principles for the persistence of (...) stuff that are general, not relying on the particular features of a kind of stuff in the way that principles for the persistence for a thing would. This provides a non-arbitrary grounding for stuff that is independent of the conditions on the nature and persistence of things the stuff composes. The principles also provide a general basis for responding to other questions about coincident stuff. (shrink)

Are the objects and events that take place in Virtual Reality genuinely real? Those who answer this question in the affirmative are realists, and those who answer in the negative are irrealists. In this paper we argue against the realist position, as given by Chalmers (2017), and present our own preferred irrealist account of the virtual. We start by disambiguating two potential versions of the realist position—weak and strong— and then go on to argue that neither is plausible. We then (...) introduce a Waltonian variety of ictionalism about the virtual, arguing that this sort of irrealist approach avoids the problems of the realist positions, fits with a unifying theory of representational works, and offers a better account of the phenomenology of engaging in virtual experiences. (shrink)

I argue that a solution to puzzles concerning the relationship ofobjects and their properties – a version of the `bundle' theory ofparticulars according to which ordinary objects are mereologicalfusions of monadic and relational tropes – is also a solution topuzzles of material constitution involving the allegedco-location of material objects. Additionally, two argumentsthat have played a prominent role in shaping the current debate,Mark Heller's argument for Four Dimensionalism and Peter vanInwagen's argument against Mereological Universalism, are shownto be unsound given this version (...) of the bundle theory. (shrink)

Philosophical questions concerning parts and wholes have received a tremendous amount of the attention of contemporary analytic metaphysicians. In what follows, I discuss some of the central questions. The questions to be discussed are: how general is parthood? Are there different kinds of parthood or ways to be a part? Can two things be composed of the same parts? When does composition occur? Can material objects gain or lose parts? What is the logical form of the parthood relation enjoyed by (...) material objects? (shrink)

Possibilism—the view that there are non-actual, merely possible entities—is a surprisingly resilient doctrine.1 One particularly hardy strand of possibilism—the modal realism championed by David Lewis—continues to attract both foes who seek to demonstrate its falsity (or at least stare its advocates into apostasy) and friends who hope to defend modal realism (or, when necessary, modify modal realism so as to avoid problematic objections).2 Although I am neither a foe nor friend of modal realism (but some of my best friends are!), (...) like many I continue to be fascinated by the doctrine. (shrink)

I argue that extended simples are possible. The argument given here parallels an argument given elsewhere for the claim that the shape properties of material objects are extrinsic, not intrinsic as is commonly supposed. In the final section of the paper, I show that if the shape properties of material objects are extrinsic, the most popular argument against extended simples fails.

In a recent paper titled ' Simples ', Ned Markosian asks and answers the Simple Question, which is, 'under what circumstances is it true of some object that it has no proper parts?' Markosian 's answer to the simple question is MaxCon, which states that an object is a simple if and only if it is a maximally continuous object. I present several arguments against MaxCon.

I argue that composition as identity is incompatible with the possibility of emergent properties (as characterized in the paper) and so should be rejected.

According to three-dimensionalism, objects persist in time by being wholly present at each time they exist; on the contrary, four-dimensionalism asserts that objects persist by having different temporal parts at different times or that they are instantaneous temporal parts of four-dimensional aggregates. Le Poidevin has argued that four-dimensionalism better accommodates two common assumptions concerning persistence and continuity; namely, that time itself is continuous and that objects persist in time in a continuous way. To this purpose, he has offered two independent (...) arguments, each of which moves from a different understanding of continuity. In this paper, both of Le Poidevin’s arguments will be discussed and rejected. (shrink)

This paper argues for including stuff in one's ontology. The distinction between things and stuff is first clarified, and then three different ontologies of the physical universe are spelled out: a pure thing ontology, a pure stuff ontology, and a mixed ontology of both things and stuff. Eleven different reasons for including stuff in one's ontology are given. Then five objections to positing stuff are considered and rejected.

This paper defends the possibility of admitting occurrents in a presentist ontology. Two ways of doing so are proposed, the first one involves Meinongian presentism. By using the notion of non-existent object and coherently modifying some mereological principle, it is argued, the presentist can allow for occurrents. The second proposal involves ex-concrete objects. Ex-concrete objects, i.e. objects that are contingently not concrete, have been used by Linsky and Zalta, 431-458, 1994), Williamson in the modal metaphysics debate, by Orilia, 589-607, 2016) (...) in the presentism-eternalism debate, and by Longenecker, 5091-5111, 2018) in the debate about material constitution. I argue that, just by admitting ex-concrete objects, it is possible to have occurrents even for the presentist. Of course, in order to do so we must modify our definitions of occurrent and continuant. Nevertheless, I argue that my theory is metaphysically sound, at least for the presentist persuaded by the intuitive claim that there are occurrents, which otherwise she must reject. (shrink)

Are there atoms in the constitution of things? Or is everything made of atomless ‘gunk’ whose proper parts have proper parts? Anaxagoras is the first gunk lover in the history of metaphysics. For him gunk is not only a theoretical possibility that cannot be ruled out in principle. Rather, it is a view that follows cogently from his metaphysical analysis of the physical world of our experience. What is distinctive about Anaxagoras’s take on gunk is not only what motives the (...) view, but also the particular type of gunk that he develops. It is qualitative gunk, rather than material gunk. Anaxagoras’s ontology was developed before matter was ‘invented’. It includes quality tropes only; they are gunky. The resulting metaphysical view – a world of qualitative gunk – is new, in the sense of being hitherto unexplored; and yet, it is derived from Anaxagoras’s writings. Drawing on Anaxagoras’s insights, this paper offers a sketch of what qualitative gunk ontology l.. (shrink)

What distinguishes a whole from an arbitrary sum of elements? I suggest a temporal and causal oriented approach. I defend two connected claims. The former is that existence is, by every means, coextensive with being the cause of a causal process. The latter is that a whole is the cause of a causal process with a joint effect. Thus, a whole is something that takes place in time. The approach endorses an unambiguous version of Restricted Composition that suits most commonsensical (...) intuitions about wholes. (shrink)

In order to avoid the problems faced by standard realist analyses of the “relation” of instantiation, Baxter and, following him, Armstrong each analyze the instantiation of a universal by a particular in terms of their partial identity. I introduce two related conceptions of partial identity, one mereological and one non-mereological, both of which require at least one of the relata of the partial identity “relation” to be complex. I then introduce a second non-mereological conception of partial identity, which allows for (...) both relata to be simple. I take these three conceptions to exhaust the plausible ways of construing two entities as being partially identical. I then argue that there is no analysis (including those offered by Baxter and Armstrong) of a universal and a particular as being partially identical consistent with any of these three conceptions that (i) is coherent, (ii) is consistently realist, (iii) does not lead to absurd consequences, and (iv) offers a “solution” to the problem of instantiation that avoids the problems with the other standard realist responses. In so arguing, I offer a criticism of the analysis of instantiation as partial identity that is independent of the standard criticism that it entails the necessity of predication. (shrink)

David Lewis claims that his theory of modality successfully reduces modal items to nonmodal items. This essay will clarify this claim and argue that it is true. This is largely an exercise within ‘Ludovician Polycosmology’: I hope to show that a certain intuitive resistance to the reduction and a set of related objections misunderstand the nature of the Ludovician project. But these results are of broad interest since they show that would-be reductionists have more formidable argumentative resources than is often (...) thought. Lewis’s reduction depends on a set of methodological commitments each of which is fairly plausible or at least currently popular, and none of which is particular to modality. The choice of which of these commitments to reject I leave to the discerning antireductionist. The essay proceeds as follows: §1 discusses reduction generally and one or two relevant puzzles; §2 discusses Lewis’s reduction in particular; the longest section, §3 replies to four objections. (shrink)

Two mereological theories are presented based on a primitive apartness relation along with binary relations of mereological excess and weak excess, respectively. It is shown that both theories are acceptable from the standpoint of constructive reasoning while remaining faithful to the spirit of classical mereology. The two theories are then compared and assessed with regard to their extensional import.

I propose a fourfold categorisation of entities according to whether or not they possess determinate identity-conditions and whether or not they are determinately countable. Some entities – which I call ‘individual objects’ – have both determinate identity and determinate countability: for example, persons and animals. In the case of entities of a kind K belonging to this category, we are in principle always entitled to expect there to be determinate answers to such questions as ‘Is x the same K as (...) y?’ and ’How many Ks are there satisfying condition C?’, even if we may sometimes be unable in practice to discover what these answers are. But other entities apparently lack either determinate identity, or determinate countability, or both. In these terms I try to explain certain important ontological differences between familiar macroscopic objects and various rather more esoteric entities, such as the ‘particles’ of quantum physics, quantities of material stuff, and tropes or property instances. (shrink)