An encyclopedia entry which covers various revisionary conceptions of which macroscopic objects there are, and the puzzles and arguments that motivate these conceptions: sorites arguments, the argument from vagueness, the puzzles of material constitution, arguments against indeterminate identity, arguments from arbitrariness, debunking arguments, the overdetermination argument, and the problem of the many.

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

I here defend microphysical manyism. According to microphysical manyism, each composite or higher-level object is a mere plurality of microphysical particles. After clarifying the commitments of the view, I offer two physicalist-friendly arguments in its favour. The first argument appeals to the Canberra Plan. Here I argue that microphysical particles acting in unison play the theoretical roles associated with composite objects - that they do everything that we think of composite objects as doing - and thus that composite objects are (...) to be identified with pluralities of microphysical particles. Along the way I rebut the objections that pluralities of particles don’t display the right emergent, ‘lingering’, or modal properties to be good candidates for identification with higher-level objects. In the second argument I claim that microphysical manyism is uniquely able to capture a compelling and widespread physicalist intuition concerning the intimate nature of the relationship between higher-level, composite objects and the microphysical world. (shrink)

Under what conditions are material objects, such as particles, parts of a whole object? This is the composition question and is a longstanding open question in philosophy. Existing attempts to specify a non-trivial restriction on composition tend to be vague and face serious counterexamples. Consequently, two extreme answers have become mainstream: composition (the forming of a whole by its parts) happens under no or all conditions. In this paper, we provide a self-contained introduction to the integrated information theory of consciousness (...) (IIT). We show that IIT specifies a non-trivial restriction on composition: composition happens when integrated information is maximized. We compare the IIT-restriction to existing proposals and argue that the IIT-restriction has significant advantages, especially in response to the problems of vagueness and counterexamples. An appendix provides an introduction to calculating parts and wholes with a simple system. (shrink)

The main idea of this thesis is multi-descriptional physicalism. According to it, only physical entities are elements of our ontology, and there are different ways to describe them. Higher-level vocabularies (e.g., mental, neurological, biological) truly describe reality. Sentences about higher-level entities are made true by physical entities. Every chapter will develop multi-descriptional physicalism or defend it from objections. In chapter 1, I will propose a new conceptual reductive account that conceptually reduces higher-level entities to physical entities. This conceptual reductive account (...) combines resources from Heil’s truthmaker theory and either a priori physicalism or a posteriori physicalism. In chapter 2, I apply this conceptual reductive account to various debates. Physicalism, the multiple-realisability argument, the prototype theory of concepts, and truthmaker explanations will be discussed. In chapter 3, I will argue that a major aim of metaphysics should be to discover which entities are fundamental and explain why they suffice for the existence of derivative entities. In chapter 4, I will propose a new way to explain why sentences apparently about composite objects are true even though there are no composite objects. It combines resources from Cameron’s truthmaker theory and van Inwagen’s paraphrase strategy. In chapter 5, I will argue that the intuition that the mind and the body are very different does not show that the mind is distinct from the body. This intuition can be explained away by mentioning our dispositions to give non-physical explanations when we are ignorant of physical facts. In chapter 6, I will examine two arguments for the existence of a metaphysically independent level, and I will argue that only a modified version of one of them succeeds. I will argue that methodological principles support the view that there is a metaphysically independent level. (shrink)

Revisionary ontologies seem to go against our common sense convictions about which material objects exist. These views face the so-called Problem of Reasonableness: they have to explain why reasonable people don’t seem to accept the true ontology. Most approaches to this problem treat the mismatch between the ontological truth and ordinary belief as superficial or not even real. By contrast, I propose what I call the “uncompromising solution”. First, I argue that our beliefs about material objects were influenced by evolutionary (...) forces that were independent of the ontological truth. Second, I draw an analogy between the Problem of Reasonableness and the New Evil Demon Problem and argue that the revisionary ontologist can always find a positive epistemic status to characterize ordinary people’s beliefs about material objects. Finally, I address the worry that the evolutionary component of my story also threatens to undermine the best arguments for revisionary ontologies. (shrink)

Gabriele Contessa has recently introduced and defended a view he calls ‘non-eliminative nihilism’. Non-eliminative nihilism is the conjunction of mereological nihilism and non-eliminativism about ordinary objects. Mereological nihilism is the thesis that composite objects do not exist, where something is a composite object just in case it has proper parts. Eliminativism about ordinary objects denies that ordinary objects exist. Eliminativism thus implies, for example, that there are no galaxies, planets, stars, ships, tables, books, organisms, cells, molecules, or atoms. Non-eliminativism is (...) the denial of eliminativism. Thus, NEN is the intriguing thesis that although composite objects do not exist, ordinary objects do. In this essay, I, first, summarize Contessa’s core support for NEN. Second, I describe two flaws in that support when it comes to organismic terms. Third, I consider and reject two possible responses on behalf of NEN’s defenders. Fourth, I show how the flaws cast doubt upon NEN itself. Finally, I offer reasons to think that if nihilism is true, then the folk have probably been trying to fix the reference of organismic terms to apparent objects within illusions. (shrink)

Mereological nihilism is the view that no objects have proper parts. Despite how counter‐intuitive it is, it is taken quite seriously, largely because it solves a number of puzzles in the metaphysics of material objects – or so its proponents claim. In this article, I show that for every puzzle that mereological nihilism solves, there is a similar puzzle that (a) it doesn’t solve, and (b) every other solution to the original puzzle does solve. Since the solutions to the new (...) puzzles apply just as well to the old puzzles, the old puzzles provide no motivation to be a mereological nihilist. (shrink)

When some objects are the parts of another object, they compose that object and that object is composite. This article is intended as an introduction to the central questions about composition and a highly selective overview of various answers to those questions. In §1, we review some formal features of parthood that are important for understanding the nature of composition. In §2, we consider some answers to the question: which pluralities of objects together compose something? As we will see, the (...) dominant answers are all of them and none of them. In §§3-4, we examine one of the main arguments that has driven philosophers to these extreme answers: the argument from vagueness. In §5, we turn to the question of whether composition is unique: is it sometimes the case that some things compose more than one thing? Finally, in §6, we turn from the question of which composites exist to the question of which composites exist fundamentally. (shrink)

According to strong composition as identity, the logical principles of one–one and plural identity can and should be extended to the relation between a whole and its parts. Otherwise, composition would not be legitimately regarded as an identity relation. In particular, several defenders of strong CAI have attempted to extend Leibniz’s Law to composition. However, much less attention has been paid to another, not less important feature of standard identity: a standard identity statement is true iff its terms are coreferential. (...) We contend that, if coreferentiality is dropped, indiscernibility is no help in making composition a genuine identity relation. To this aim, we analyse as a case study Cotnoir’s theory of general identity, in which indiscernibility is obtained thanks to a revisionary semantics and true identity statements are allowed to connect non-coreferential terms. We extend Cotnoir’s strategy for indiscernibility to the relation of comaternity, and we show that, neither in the case of composition nor in that of comaternity, indiscernibility contibutes to show that they are genuine identity relations. Finally, we compare Cotnoir’s approach with other versions of strong CAI endorsed by Wallace, Bøhn, and Hovda, and canvass the extent to which they violate coreferentiality. The comparative analysis shows that, in order to preserve coreferentiality, strong CAI is forced to adopt a non-standard semantic treatment of the singular/plural distinction. (shrink)

A compositional nihilist believes that the only objects that exist are simples. However, a non-nihilist believes in the existence of composite objects and challenges the nihilist to explain why there are true sentences about chairs, tables, etc., if composite objects do not exist. Different nihilist views have been suggested to explain this (the paraphrase strategy and the truthmaker theory), but I believe that they are unsuccessful (either they do not successfully paraphrase every sentence apparently about composite objects, or they are (...) not precise about the truthmakers of those sentences). I will suggest that a new truthmaker theory, which uses resources from Cameron’s truthmaker theory and van Inwagen’s paraphrase strategy, can give such an explanation and does not face the problems of other theories. Therefore, we have a good reason to accept this truthmaker theory as the best nihilist way to accommodate sentences apparently about composite objects. (shrink)

Peter van Inwagen has in recent decades made significant and influential contributions to metaphysics. In his Material Beings he advanced a novel ontology according to which chairs and other medium-sized dry goods don’t really exist. He went on to make important contributions to metaontology. Parts of his Ontology, Identity, and Modality and Existence: Essays in Ontology defend a broadly Quinean conception of existence questions and how to address them. I argue that the metaontology articulated in those later works is in (...) fact inconsistent with his defense of his ontology advanced in his earlier work. (shrink)