When do several objects compose a further object? The last twenty years have seen a great deal of discussion of this question. According to the most popular view on the market, there is a physical object composed of your brain and Jeremy Bentham’s body. According to the second-most popular view on the market, there are no such objects as human brains or human bodies, and there are also no atoms, rocks, tables, or stars. And according to the third-ranked view, there (...) are human bodies, but still no brains, atoms, rocks, tables, or stars. Although it’s pleasant to have so many crazy-sounding views around, I think it would also be nice to have a commonsense option available. The aim of this paper is to offer such an option. The approach I offer begins by considering a mereological question other than the standard one that has been the focus of most discussions in the literature. I try to show that the road to mereological sanity begins with giving the most straightforward and commonsensical answer to this other question, and then extending that answer to further questions about the mereology of physical objects. On the approach I am recommending, it turns out that all of the mereological properties and relations of physical objects are determined by their spatial properties and relations. (shrink)

Do mereological fusions have their parts necessarily? None of the axioms of non-modal formulations of classical mereology appear to speak directly to this question. And yet a great many philosophers who take the part-whole relation to be governed by classical mereology seem to assume that they do. In addition to this, many philosophers who make allowance for the part-whole relation to obtain merely contingently between a part and a mereological fusion tend to depart from non-modal formulations of classical (...) mereology at least when it comes to the axiom of Unique Fusion, which states that no two different mereological fusions ever fuse exactly the same objects. This is no coincidence. There are reasons of principle why one’s adherence to classical mereology should exert some pull towards the view that mereological fusions have their parts necessarily. There is, however, no direct route from the combination of classical mereology and propositional modal logic to the hypothesis that the part-whole relation obtains necessarily between a part and a mereological fusion. In order to bridge between a modal formulation of classical mereology and the hypothesis that fusions have their parts necessarily, one needs to strengthen the axiom of Unrestricted Fusion in a way that is agreeable to many philosophers on both sides of the debate. (shrink)

When do the folk think that mereological composition occurs? Many metaphysicians have wanted a view of composition that fits with folk intuitions, and yet there has been little agreement about what the folk intuit. We aim to put the tools of experimental philosophy to constructive use. Our studies suggest that folk mereology is teleological: people tend to intuit that composition occurs when the result serves a purpose. We thus conclude that metaphysicians should dismiss folk intuitions, as tied into a (...) benighted teleological view of nature. (shrink)

An overview of contemporary part-whole theories, with reference to both their axiomatic developments and their philosophical underpinnings.

Classical mereology is a formal theory of the part-whole relation, essentially involving a notion of mereological fusion, or sum. There are various different definitions of fusion in the literature, and various axiomatizations for classical mereology. Though the equivalence of the definitions of fusion is provable from axiom sets, the definitions are not logically equivalent, and, hence, are not inter-changeable when laying down the axioms. We examine the relations between the main definitions of fusion and correct some technical errors (...) in prominent discussions of the axiomatization of mereology. We show the equivalence of four different ways to axiomatize classical mereology, using three different notions of fusion. We also clarify the connection between classical mereology and complete Boolean algebra by giving two "neutral" axiom sets which can be supplemented by one or the other of two simple axioms to yield the full theories; one of these uses a notion of "strong complement" that helps explicate the connections between the theories. (shrink)

Multilocation and Minimal Mereology do not mix well. It has been pointed out that Three-Dimensionalism, which can be construed as multilocation-friendly, runs into trouble with Weak Supplementation. But in fact, regardless of one’s theory of persistence, if someone posits the possibility of any one of several kinds of multilocation, he or she will not be able to maintain the necessity of any of the three axioms of Minimal Mereology: the Transitivity of Proper Parthood, the Asymmetry of Proper Parthood, (...) and Weak Supplementation. In fact, positing even the mere conceivability of cases involving multilocation will require the denial of the analyticity of Minimal Mereology. In response to this, some have claimed that we ought to relativise parthood, either to one region or to two. Unfortunately, if we replace the axioms of Minimal Mereology with region-relativised counterparts, we will not be able to capture the intuitions that supported the original axioms. The only adequate solution, I maintain, is to restrict multilocation to a domain outside the scope of the rules we intuitively take to govern the parthood relation. For those who take Minimal Mereology to be necessary and universal, that will mean relinquishing the possibility of multilocation. (shrink)

This paper is a systematic exploration of non-wellfounded mereology. Motivations and applications suggested in the literature are considered. Some are exotic like Borges’ Aleph, and the Trinity; other examples are less so, like time traveling bricks, and even Geach’s Tibbles the Cat. The authors point out that the transitivity of non-wellfounded parthood is inconsistent with extensionality. A non-wellfounded mereology is developed with careful consideration paid to rival notions of supplementation and fusion. Two equivalent axiomatizations are given, and are (...) compared to classical mereology. We provide a class of models with respect to which the non-wellfounded mereology is sound and complete. (shrink)

Parthood and composition are everywhere. The leg of a table is part of the table, the word "Christmas" is part of the sentence "I wish you a merry Christmas", the 13th century is part of the Middle Ages. The Netherlands, Belgium, and Luxembourg compose Benelux, the body of a deer is composed of a huge number of cells, the Middle Ages are composed of the Early Middle Ages, High Middle Ages, and Late Middle Ages. Is there really a general theory (...) covering every instance of parthood and composition? Is classical mereology this general theory? Are its seemingly counter-intuitive features serious defects? -/- Mereology: A Philosophical Introduction addresses the multifaceted and lively philosophical debates surrounding these questions, and defends the idea that classical mereology is indeed the general and exhaustive theory of parthood and composition in the domain of concrete entities. -/- Several examples of parthood and composition, involving entities of different kinds, are scrutinised in depth. Incidentally, mereology is shown to interact in a surprising way with metaontology. Presenting a well-organized and comprehensive discussion of parthood and related notions, Mereology: A Philosophical Introduction contributes to a better understanding of a subject central to contemporary metaphysics. (shrink)

Paul Hovda’s excellent paper ‘What Is Classical Mereology?' has fruitfully reshaped the debate concerning the axiomatic foundations of classical mereology. Precisely because of the importance of Hovda’s work and its usefulness as a reference tool, we note here that one of the five axiom systems presented therein, corresponding the ‘Third Way’ to classical mereology, is defective and must be amended. In addition, we note that two other axiom systems, corresponding to the ‘First Way’ and to the ‘Fifth (...) Way’, involve redundancies. (shrink)

We present a new axiomatization of classical mereology in which the three components of the theory—ordering, composition, and decomposition prin-ciples—are neatly separated. The equivalence of our axiom system with other, more familiar systems is established by purely deductive methods, along with additional results on the relative strengths of the composition and decomposition axioms of each theory.

This paper provides a detailed examination of Kit Fine’s sizeable contribution to the development of a neo‐Aristotelian alternative to standard mereology; I focus especially on the theory of ‘rigid’ and ‘variable embodiments’, as defended in Fine 1999. Section 2 briefly describes the system I call ‘standard mereology’. Section 3 lays out some of the main principles and consequences of Aristotle’s own mereology, in order to be able to compare Fine’s system with its historical precursor. Section 4 gives (...) an exposition of Fine’s theory of embodiments and goes on to isolate a number of potential concerns to which this account gives rise. In particular, I argue that Fine’s theory threatens to proliferate primitive sui generis relations of parthood and composition, whose characteristics must be stipulatively imposed on them, relative to particular domains; given its ‘superabundance’ of objects, Fine’s system far outstrips the already inflated ontological commitments of standard mereology; and there is a legitimate question as to why we should consider Fine’s primitive and sui generis relations of parthood and composition to be genuinely mereological at all, given their formal profile. These three objections lead me to conclude that we ought to explore other avenues that preserve the highly desirable, hylomorphic, features of Fine’s mereology, while avoiding its methodological and ontological excesses. (shrink)

My approach to the exposition of Brentano's mereology is to first introduce the basics of Classical Mereology and then point out the respects in which Brentano's mereology deviates from it. There are two such respects: first, Brentano rejects the axiom of supplementation; second, he distinguishes two primitive notions of parthood.

In this paper it is shown that Heyting and Co-Heyting mereological systems provide a convenient conceptual framework for spatial reasoning, in which spatial concepts such as connectedness, interior parts, (exterior) contact, and boundary can be defined in a natural and intuitively appealing way. This fact refutes the wide-spread contention that mereology cannot deal with the more advanced aspects of spatial reasoning and therefore has to be enhanced by further non-mereological concepts to overcome its congenital limitations. The allegedly unmereological concept (...) of boundary is treated in detail and shown to be essentially affected by mereological considerations. More precisely, the concept of boundary turns out to be realizable in a variety of different mereologically grounded versions. In particular, every part K of a Heyting algebra H gives rise to a well-behaved K-relative boundary operator. (shrink)

This paper explores the mereology of structural universals, using the structural richness of a non-classical mereology without unique fusions. The paper focuses on a problem posed by David Lewis, who using the example of methane, and assuming classical mereology, argues against any purely mereological theory of structural universals. The problem is that being a methane molecule would have to contain being a hydrogen atom four times over, but mereology does not have the concept of the same (...) part occurring several times. This paper takes up the challenge by providing mereological analysis of three operations sufficient for a theory of structural universals: Reflexive binding, i.e. identifying two of the places of a universal; Existential binding, i.e. the language-independent correlate of an existential quantification; and Conjunction. (shrink)

Part One of this paper is a case against classical mereology and for Heyting mereology. This case proceeds by first undermining the appeal of classical mereology and then showing how it fails to cohere with our intuitions about a measure of quantity. Part Two shows how Heyting mereology provides an account of sets and classes without resort to any nonmereological primitive.

Abstract 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 Hm is maximally acceptable for nominalistic mereology. In an extension Hgem of Hm, a modal analog for the classical systems of Leonard and Goodman (J Symb Log 5:45–55, 1940) and Lesniewski (1916) is introduced and shown to be complete with respect to 0- deleted Boolean algebras. We (...) characterize the formulas of first-order logic invariant for Hgem-bisimulations. (shrink)

Core principles of mereology have been questioned by appealing to time travel scenarios. This paper questions the methodology of employing time travel scenarios to argue against mereology. We show some time travel scenarios are structurally equivalent to more standard ones not involving time travel; and that the three main theories about persistence through time can each solve both the time travel scenario as well as the structurally similar classical scenario. Time travel scenarios that are not similar to more (...) standard arguments are instead problematic because they are open to different, incompatible interpretations. We conclude that compared to the classical arguments against mereological principles, time travel scenarios do not add anything new. (shrink)

The signature of the formal language of mereology contains only one binary predicate P which stands for the relation “being a part of”. Traditionally, P must be a partial ordering, that is, ${\forall{x}Pxx, \forall{x}\forall{y}((Pxy\land Pyx)\to x=y)}$ and ${\forall{x}\forall{y}\forall{z}((Pxy\land Pyz)\to Pxz))}$ are three basic mereological axioms. The best-known mereological theory is “general extensional mereology”, which is axiomatized by the three basic axioms plus the following axiom and axiom schema: (Strong Supplementation) ${\forall{x}\forall{y}(\neg Pyx\to \exists z(Pzy\land \neg Ozx))}$ , where Oxy (...) means ${\exists z(Pzx\land Pzy)}$ , and (Fusion) ${\exists x\alpha \to \exists z\forall y(Oyz\leftrightarrow \exists x(\alpha \land Oyx))}$ , for any formula α where z and y do not occur free. In this paper, I will show that general extensional mereology is decidable, and will also point out that the decidability of the first-order approximation of the theory of complete Boolean algebras can be shown in the same way. (shrink)

In this paper† we will treat mereology as a theory of some structures that are not axiomatizable in an elementary langauge and we will use a variable rangingover the power set of the universe of the structure). A mereological structure is an ordered pair M = hM,⊑i, where M is a non-empty set and ⊑is a binary relation in M, i.e., ⊑ is a subset of M × M. The relation ⊑ isa relation of being a mereological part . (...) We formulate an axiomatization of mereological structures, different from Tarski’s axiomatization aspresented in [10] . We prove that these axiomatizations are equivalent . Of course, these axiomatizations are definitionally equivalent to thevery first axiomatization of mereology from [5], where the relation of being aproper part ⊏ is a primitive one.Moreover, we will show that Simons’ “Classical Extensional Mereology”from [9] is essentially weaker than Leśniewski’s mereology. (shrink)

Lewis famously argued that mereology is ontologically innocent. Many who have considered this claim believe he was mistaken. Mereology is not innocent, because its acceptance entails the acceptance of sums, new objects that were not previously part of one’s ontology. This argument, the argument from ontological parsimony, has two versions: a qualitative and a quantitative one. I argue that the defender of mereology can neutralize both arguments by holding that, given mereology, a commitment to the parts (...) of an object is not an extra ontological commitment, made in addition to the commitment to the object; and that if the parts of an object are ‘ontologically innocent’, then sums cannot fail to be innocent either. (shrink)

Weatherson argues that whoever accepts classical logic, standard mereology and the difference between vague objects and any others, should conclude that there are no vague objects. Barnes and Williams claim that a supporter of vague objects who accepts classical logic and standard mereology should recognize that the existence of vague objects implies indeterminate identity. Even though it is not clearly stated, they all seem to be committed to the assumption that reality is ultimately constituted by mereological atoms. This (...) assumption is not granted by standard mereology which instead remains silent on whether reality is atomic or gunky; therefore, I contend that whoever maintains classical logic, standard mereology and the difference between vague objects and any others, is not forced to conclude with Weatherson that there are no vague objects; nor is she compelled to revise her point of view according to Barnes and Williams’s proposal and to accept that the existence of vague objects implies indeterminate identity. (shrink)

Classical mereology (CM) is usually taken to be formulated in a tenseless language, and is therefore associated with a four-dimensionalist metaphysics. This paper presents three ways one might integrate the core idea of flat plenitude, i.e., that every suitable condition or property has exactly one mereological fusion, with a tensed logical setting. All require a revised notion of mereological fusion. The candidates differ over how they conceive parthood to interact with existence in time, which connects to the distinction between (...) endurance and perdurance. Similar issues arise for the integration of mereology with modality, and much of our discussion applies to this project as well. (shrink)

This article is devoted to the problem of ontological foundations of three-dimensional Euclidean geometry. Starting from Bertrand Russell’s intuitions concerning the sensual world we try to show that it is possible to build a foundation for pure geometry by means of the so called regions of space. It is not our intention to present mathematically developed theory, but rather demonstrate basic assumptions, tools and techniques that are used in construction of systems of point-free geometry and topology by means of (...) class='Hi'>mereology and Whitehead-like connection structures. We list and briefly analyze axioms for mereological structures, as well as those for connection structures. We argue that mereology is a good tool to model so called spatial relations. We also try to justify our choice of axioms for connection relation. Finally, we briefly discuss two theories: Grzegorczyk’s point-free topology and Tarski’s geometry of solids. (shrink)

In Lewis reconstructs set theory using mereology and plural quantification (MPQ). In his recontruction he assumes from the beginning that there is an infinite plurality of atoms, whose size is equivalent to that of the set theoretical universe. Since this assumption is far beyond the basic axioms of mereology, it might seem that MPQ do not play any role in order to guarantee the existence of a large infinity of objects. However, we intend to demonstrate that mereology (...) and plural quantification are, in some ways, particularly relevant to a certain conception of the infinite. More precisely, though the principles of mereology and plural quantification do not guarantee the existence of an infinite number of objects, nevertheless, once the existence of any infinite object is admitted, they are able to assure the existence of an uncountable infinity of objects. So, ifMPQ were parts of logic, the implausible consequence would follow that, given a countable infinity of individuals, logic would be able to guarantee an uncountable infinity of objects. (shrink)

Based on their research showing that growing cities follow basic principles, two theoretical physicists, Luis Bettencourt and Geoffrey West, call for researchers and professionals to contribute to a grand theory of urban sustainability. In their research, they develop a ‘science of the city’ to help urban planners address problems that arise from population increases. Although they provide valuable insights for understanding urban sustainability issues, they do not give planners a manageable way to approach such problems. I argue that developing an (...) applied mereology to understand the concept of ‘city identity’ gives planners a theoretical device for addressing urban affairs, including ethical concerns. In turn, I devise a model of city identity to show how a ‘philosophy of the city’ contributes to a grand theory of urban sustainability. (shrink)

We present a sequent calculus for extensional mereology. It extends the classical first-order sequent calculus with identity by rules of inference corresponding to well-known mereological axioms. Structural rules, including cut, are admissible.

Mereotopology is that branch of the theory of regions concerned with topological properties such as connectedness. It is usually developed by considering the parthood relation that characterizes the, perhaps non-classical, mereology of Space (or Spacetime, or a substance filling Space or Spacetime) and then considering an extra primitive relation. My preferred choice of mereotopological primitive is interior parthood . This choice will have the advantage that filters may be defined with respect to it, constructing “points”, as Peter Roeper has (...) done (“Region-based topology”, Journal of Philosophical Logic , 26 (1997), 25–309). This paper generalizes Roeper’s result, relying only on mereotopological axioms, not requiring an underlying classical mereology, and not assuming the Axiom of Choice. I call the resulting mathematical system an approximate lattice , because although meets and joins are not assumed they are approximated. Theorems are proven establishing the existence and uniqueness of representations of approximate lattices, in which their members, the regions, are represented by sets of “points” in a topological “space”. (shrink)

This study is in two parts. In the first part, various important principles of classical extensional mereology are derived on the basis of a nice axiomatization involving ‘part of’ and fusion. All results are proved here with full Fregean rigor. They are chosen because they are needed for the second part. In the second part, this natural-deduction framework is used in order to regiment David Lewis’s justification of his Division Thesis, which features prominently in his combination of mereology (...) with class theory. The Division Thesis plays a crucial role in Lewis’s informal argument for his Second Thesis in his book Parts of Classes. In order to present Lewis’s argument in rigorous detail, an elegant new principle is offered for the theory that combines class theory and mereology. The new principle is called the Canonical Decomposition Thesis. It secures Lewis’s Division Thesis on the strong construal required in order for his argument to go through. The exercise illustrates how careful one has to be when setting up the details of an adequate foundational theory of parts and classes. The main aim behind this investigation is to determine whether an anti-realist, inferentialist theorist of meaning has the resources to exhibit Lewis’s argument for his Second Thesis—which is central to his marriage of class theory with mereology—as a purely conceptual one. The formal analysis shows that Lewis’s argument, despite its striking appearance to the contrary, can be given in the constructive, relevant logic IR. This is the logic that the author has argued, elsewhere, to be the correct logic from an anti-realist point of view. The anti-realist is therefore in a position to regard Lewis’s argument as purely conceptual. (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.

We consider a set-theoretic version of mereology based on the inclusion relation ⊆ and analyze how well it might serve as a foundation of mathematics. After establishing the non-definability of ∈ from ⊆, we identify the natural axioms for ⊆-based mereology, which constitute a finitely axiomatizable, complete, decidable theory. Ultimately, for these reasons, we conclude that this form of set-theoretic mereology cannot by itself serve as a foundation of mathematics. Meanwhile, augmented forms of set-theoretic mereology, such (...) as that obtained by adding the singleton operator, are foundationally robust. (shrink)

The present article provides a mereological analysis of Euclid’s planar geometry as presented in the first two books of his Elements. As a standard of comparison, a brief survey of the basic concepts of planar geometry formulated in a set-theoretic framework is given in Section 2. Section 3.2, then, develops the theories of incidence and order using a blend of mereology and convex geometry. Section 3.3 explains Euclid’s “megethology”, i.e., his theory of magnitudes. In Euclid’s system of geometry, megethology (...) takes over the role played by the theory of congruence in modern accounts of geometry. Mereology and megethology are connected by Euclid’s Axiom 5: “The whole is greater than the part.” Section 4 compares Euclid’s theory of polygonal area, based on his “Whole-Greater-Than-Part” principle, to the account provided by Hilbert in his Grundlagen der Geometrie. An hypothesis is set forth why modern treatments of geometry abandon Euclid’s Axiom 5. Finally, in Section 5, the adequacy of atomistic mereology as a framework for a formal reconstruction of Euclid’s system of geometry is discussed. (shrink)

This peer reviewed reference article is an annotated online bibliography on mereology with 80+ entries. It's aim is to provide a selective and balanced guide to the subject. It contains thematic headings with commentaries. The reader should come away cognizant of what the most influential work in mereology are. Topics highlighted herein include, but are not limited to: the history of mereology, classical extensional mereology and its challenges, parthood, connections with location relations, mereological simples and gunk, (...) composition as identity, as well as mereological essentialism, nihilism, and universalism. (shrink)

In continuing with the research program initiated by Llored and Harré of exploring the part/whole discourses of chemistry, we analyse Quantitative Structure-Activity Relationships studies, which are widespread approaches for modeling substances’ properties. The study is carried out by analyzing a particular QSAR model, and it is found that different mereologies are needed: from those regarding bulk substances as wholes and molecular entities as parts and to mereologies where the wholes are molecules whose parts are atoms, structured subsets of atoms, nuclei (...) and electronic densities. We suggest a relationship between successful QSAR models and a deep understanding of the mereologies used and the ways they are intertwined. We note that QSAR modelers prefer the mereology of substance-molecule and then discuss how that is related to simplicity and computational capacity. Historical questions are opened, e.g. how the mereologies of substances have changed over time? and why they are mostly oriented toward organic chemistry? (shrink)

David Lewis insists that restrictivist composition must be motivated by and occur due to some intuitive desiderata for a relation R among parts that compose wholes, and insists that a restrictivist’s relation R must be vague. Peter van Inwagen agrees. In this paper, I argue that restrictivists need not use such examples of relation R as a criterion for composition, and any restrictivist should reject a number of related mereological theses. This paper critiques Lewis and van Inwagen (and others) on (...) their respective mereological metaphysics, and offers a Golden Mean between their two opposite extremes. I argue for a novel account of mereology I call Modal Mereology that is an alternative to Classical Mereology. A modal mereologist can be a universalist about the possible composition of wholes from parts and a restrictivist about the actual composition of wholes from parts. I argue that puzzles facing Modal Mereology (e.g., puzzles concerning Cambridge changes and the Problem of the Many, and how to demarcate the actual from the possible) are also faced in similar forms by classical universalists. On my account, restricted composition is rather motivated by and occurs due to a possible whole’s instantiating an actual type. Universalists commonly believe in such types and defend their existence from objections and puzzles. The Modal Mereological restrictivist can similarly defend the existence of such types (adding that such types are the only wholes) from similar objections and puzzles. (shrink)

The paper set up a small “philosophical lab” for thought experiments using Digital Universes as its main tool. Digital Universes allow us to examine how mereology affects the debate on New Realism of Ferraris and shed new light on the whole notion of Realism. The semi-formal framework provides a convenient way to model the varieties of realism that are important for the program of New Realism: we then draw the natural consequences of this approach into the ontology of our (...) world, arguing that the same considerations that apply to Digital Universe would hold for chess, institutions and social objects as well. Once a particular version of mereology is chosen, there are unavoidable consequences that the very underlying structure of social ontology. We then propose a new New Realism to tackle social objects: social objects turn out to be nothing more than mereological sums, picked up by some description. (shrink)

This paper deals with the treatment of infinity and finiteness in mereology. After an overview of some first-order mereological theories, finiteness axioms are introduced along with a mereological definition of “x is finite” in terms of which the axioms themselves are derivable in each of those theories. The finiteness axioms also provide the background for definitions of “ T makes an assumption of infinity”. In addition, extensions of mereological theories by the axioms are investigated for their own sake. In (...) the final part, a definition of “x is finite” stated in a second-order language is also presented, followed by some concluding remarks on the motivation for the study of the extensions of mereological theories dealt with in the paper. (shrink)

In the third Logical Investigation Husserl presents an integrated theory of wholes and parts based on the notions of dependency, foundation ( Fundierung ), and aprioricity. Careful examination of the literature reveals misconceptions regarding the meaning and scope of the central axis of this theory, especially with respect to its proper context within the development of Husserl's thought. The present paper will establish this context and in the process correct a number of these misconceptions. The presentation of mereology in (...) the Logical Investigations will be shown to originate largely from Husserl's implicit self-criticism of his prior views on the unity of a whole presented in his first work, Philosophy of Arithmetic. (shrink)

We show that a standard axiomatization of mereology is equivalent to the condition that a topological space is discrete, and consequently, any model of general extensional mereology is indistinguishable from a model of set theory. We generalize these results to the Cartesian closed category of convergence spaces.

The paper explores the proof theory of non-wellfounded mereology with binary fusions and provides a cut-free sequent calculus equivalent to the standard axiomatic system.

In his book, 'History as a Science and the System of the Sciences', Thomas Seebohm articulates the view that history can serve to mediate between the sciences of explanation and the sciences of interpretation, that is, between the natural sciences and the human sciences. Among other things, Seebohm analyzes history from a phenomenological perspective to reveal the material foundations of the historical human sciences in the lifeworld. As a preliminary to his analyses, Seebohm examines the formal and material presuppositions of (...) phenomenological epistemology, as well as the emergence of the human sciences and the traditional distinctions and divisions that are made between the natural and the human sciences. -/- As part of this examination, Seebohm devotes a section to discussing Husserl’s formal mereology because he understands that a reflective analysis of the foundations of the historical sciences requires a reflective analysis of the objects of the historical sciences, that is, of concrete organic wholes (i.e., social groups) and of their parts. Seebohm concludes that Husserl’s mereological ontology needs to be altered with regard to the historical sciences because the relations between organic wholes and their parts are not summative relations. Seebohm’s conclusion is relevant for the issue of the reducibility of organic wholes such as social groups to their parts and for the issue of the reducibility of the historical sciences to the lower-order sciences, that is, to the sciences concerned with lower-order ontologies. -/- In this paper, I propose to extend Seebohm’s conclusion to the ontology of chemical wholes as object of quantum chemistry and to argue that Husserl’s formal mereology is descriptively inadequate for this regional ontology as well. This may seem surprising at first, since the objects studied by quantum chemists are not organic wholes. However, my discussion of atoms and molecules as they are understood in quantum chemistry will show that Husserl’s classical summative and extensional mereology does not accurately capture the relations between chemical wholes and their parts. This conclusion is relevant for the question of the reducibility of chemical wholes to their parts and of the reducibility of chemistry to physics, issues that have been of central importance within the philosophy of chemistry for the past several decades. (shrink)

The present volume is the first comprehensive reference work for research on part-whole relations. The Handbook of Mereology offers a wide scope, inclusive presentation of contemporary research on part-whole relations that draws out systematic, historical, and interdisciplinary trajectories, shows the subject’s fertility, and inspires future explorations. In particular, we want to impress that mereology is much more than the study of axiomatised systems. The relationship between part and whole is a basic schema of cognitive organisation that operates not (...) only at the level of language and propositional thought, but also at the level of sensory input processing, especially visual and auditory. In the natural, social, and human sciences, as well as in the Humanities, part-whole relations organize all three: data domains, methods, and theories. In short, part-whole relations play a fundamental role in how we perceive and interact with nature, how we speak and think about the world and ourselves, as societies and as individuals. (shrink)

In this thesis I argue against unrestricted mereological hybridism, the view that there are absolutely no constraints on wholes having parts from many different logical or ontological categories, an exemplar of which I take to be ‘mixed fusions’. These are composite entities which have parts from at least two different categories – the membered (as in classes) and the non-membered (as in individuals). As a result, mixed fusions can also be understood to represent a variety of cross-category summation such as (...) the abstract with the concrete, the physical with the non-physical, and the possible with the impossible, just to name a few. -/- Proposed by David Lewis (1991) alongside his defence of classical mereology (the major theory of parthood which permits such transcategorial composites through its principle of unrestricted composition) it is my contention that mixed fusions are an under-examined consequence of indiscriminate mereological fusion which harbour a multitude of complications. In my attempt to discern their substantive character, throughout this thesis I make a case study of mixed fusions and uncover several problematic consequences which I think follow from their most plausible assessment. -/- These include: (1) that mixed fusions’ probable membership relations may lead to dubious foundational loops in the mereological Universe, or (2) otherwise that mixed fusions oblige an implausible ontological priority of the mereological Universe as a whole; (3) that mixed fusions contradict the reductive account of set theory they are proposed within, by plausibly being seen to have the same members as their class parts, and (4) that mixed fusions therefore confound a mereological thesis of Composition as Identity, which some (including Lewis) use to support classical mereology – a consequence which is potentially self-defeating; (5) that mixed fusions as sums of abstract and concrete entities both subvert Lewis’s (1986) system of modal realism, while (6) also undermining less expansive theories of possible worlds; and finally, (7) that even where some of the foregoing is resisted, it remains implausible that mixed fusions are ontologically innocent, because their supposed distinction from their parts in this case ensures that they need to be counted as additional entities in one’s ontology. -/- To be clear, I do not advance a theory of mereological hybrid nihilism in the sense of denying all cases of transcategorial composition. (I only cover a few select instances of mereological hybridism via mixed fusions after all.) Rather, I deny that mereological hybridism is plausible in full generality, by demonstrating that any cases of it are at least limited by the constraints that I identify. This in turn vindicates a call for a restriction on parthood theories and composition principles which allow certain types of categorially mixed entities – including restricting classical mereology with its principle of unrestricted composition. -/- Although theories of parthood like the standard classical mereology are not ordinarily developed for the sake of mereological hybrids like mixed fusions, these and other transcategorial composites are still among the logical consequences of such parthood systems operating with sufficient generality. The significance of my thesis, then, comes from showcasing how some of these kinds of entities do not conform to the systems in which they are included as required, and hence I argue for the rejection of unrestricted mereological hybridism as well as any mereological principles which support it. (shrink)

The debate about the ontological innocence of mereology has generally been framed as a debate about the plausibility of Universal Fusion. Ontologically loaded fusions must be more than the sum of their parts, and this seems to violate parsimony if fusion is universal. Less attention has been paid to the question of what sort of emergence mereological fusions must exhibit if they are irreducible to their parts. The philosophy of science literature provides several models of such strong emergence. Examining (...) those models suggests that the difficulty with emergent fusions has at least as much to do with extensionality as it does with Universal Fusion. Some accounts of emergence fail to ensure irreducibility when combined with extensional mereologies. The most promising model for the strong emergence of ontologically loaded fusions fails to validate Anti-Symmetry, which naturally leads to failures of extensionality. These results suggest that the focus on Universal Fusion may have been misplaced. (shrink)

Mereological nihilism is the thesis that composition never occurs. Sider has defended nihilism on the basis of its relative ideological simplicity. In this paper I develop the argument from ideological simplicity, and defend it from some recent objections. Along the way I discuss the best way to formulate nihilism, what it means for a theory to exhibit lesser or greater degrees of ideological simplicity, the relationship between the parthood relation and the identity relation, and the notion that we should judge (...) the ideological simplicity of competing theories on the basis of the kinds of ideological commitments required by those theories. (shrink)

The interpretation of Lewis‘s doctrine of natural properties is difficult and controversial, especially when it comes to the bearers of natural properties. According to the prevailing reading – the minimalist view – perfectly natural properties pertain to the micro-physical realm and are instantiated by entities without proper parts or point-like. This paper argues that there are reasons internal to a broadly Lewisian kind of metaphysics to think that the minimalist view is fundamentally flawed and that a liberal view, according to (...) which natural properties are instantiated at several or even at all levels of reality, should be preferred. Our argument proceeds by reviewing those core principles of Lewis‘s metaphysics that are most likely to constrain the size of the bearers of natural properties: the principle of Humean supervenience, the principle of recombination in modal realism, the hypothesis of gunk, and the thesis of composition as identity. (shrink)

I provide a classification of varieties of pantheism. I argue that there are two different kinds of commitments that pantheists have. On the one hand, there is an ontological commitment to the existence of a sum of all things. On the other hand, there is an ideological commitment: either collectively or distributively, the sum of all things is divine.

While there is a growing philosophical interest in analysing olfactory experiences, the mereological structure of odours considered in respect of how they are perceptually experienced has not yet been extensively investigated. The paper argues that odours are perceptually experienced as having a mereological structure, but this structure is significantly different from the spatial mereological structure of visually experienced objects. Most importantly, in the case of the olfactory part-structure, the classical weak supplementation principle is not satisfied. This thesis is justified by (...) referring to empirical results in olfactory science concerning the human ability to identify components in complex olfactory stimuli. Further, it is shown how differences between olfactory and visual mereologies may arise from the way in which these modalities represent space. (shrink)

The goal of this paper is to raise a few questions about Bayne s mereological account of the unity of consciousness. In Section 1, I raise a few clarificatory questions about the account and the thesis that consciousness is necessarily unified. In Sections 2 and 3, I offer an alternative view of unity of consciousness and contrast it with Bayne's view. I call this view the connectivity account. These sections prepare the ground for the main question of this article: why (...) should we prefer Bayne's mereological view to the connectivity view? (shrink)