A compact overview of the main formal theories of parthood and of their mutual relationships, up to Classical Extensional Mereology. Written as an Appendix to the other essays included in the volume.

In this paper I argue that composition as identity entails unrestricted composition. I also briefly consider a new take on the special composition question.

Many of us think that ordinary objects – such as tables and chairs – exist. We also think that ordinary objects have parts: my chair has a seat and some legs as parts, for example. But once we are committed to the (seemingly innocuous) thesis that ordinary objects are composed of parts, we then open ourselves up to a whole host of philosophical problems, most of which center on what exactly the composition relation is. Composition as Identity (CI) is the (...) view that the composition relation is the identity relation. While such a view has some advantages, there are many arguments against it. In this essay, I will briefly canvass three different varieties of Composition as Identity, and suggest why one of them should be preferred over the others. Then I will outline several versions of the most common objection against CI. I will suggest how a CI theorist can respond to these charges by maintaining that some of the arguments are invalid. (In part 2, I show how a CI theorist can maintain that the remaining arguments, while valid, are unsound). (shrink)

In this paper I argue that we need to take irreducibly plural logic more seriously in metaphysical debates due to the fact that the verdict of many metaphysical debates hangs on it. I give two examples. The main example I focus on is the debate recently revived by Jonathan Schaffer over the fundamental cardinality of the world. I show how the three main arguments provided by Schaffer are unsound in virtue of an employment of plural logic. The second example I (...) give is a more general issue about the possibility of emergent properties of mereological wholes. Employing plural logic there is a new way to understand such cases. The upshot is that plural logic greatly matters to metaphysics and hence can no longer be ignored the way it has in this area. (shrink)

Although the relationship of part to whole is one of the most fundamental there is, this is the first full-length study of this key concept. Showing that mereology, or the formal theory of part and whole, is essential to ontology, Simons surveys and critiques previous theories--especially the standard extensional view--and proposes a new account that encompasses both temporal and modal considerations. Simons's revised theory not only allows him to offer fresh solutions to long-standing problems, but also has far-reaching consequences for (...) our understanding of a host of classical philosophical concepts. (shrink)

The topic of this book is material objects. Like most interesting concepts, the concept of a material object is one without precise boundaries.

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)

This collection of essays is the first of its kind to focus on the relationship between composition and identity. Twelve original articles--written by internationally renowned scholars and rising stars in the field--argue for and against the controversial doctrine that composition is identity.--Provided by publisher.

Some mereologists boast that their view of parts and wholes is ontologically innocent.[Lewis 1991: 72-87] They claim that a fusion is nothing over and above its parts; once you’ve committed to the parts, you get the fusion for free. In other words, fusions are not a further ontological commitment beyond the commitment to the parts. There are various proposals to explain how it is that fusions can come about so cheap. Perhaps the most straightforward of these explanations, and the one (...) I will be concerned with in this paper, is to accept the Strong Composition Thesis:2, 3.. (shrink)

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

Many philosophers think not. Many philosophers, in fact, seem to suppose that anyone who raises the question whether mereological sums can change their parts displays thereby a failure to grasp an essential feature of the concept “mereological sum.” It is hard to point to an indisputable example of this in print,[i] but it is a thesis I hear put forward very frequently in conversation (sometimes it is put forward in the form of an incredulous stare after I have said something (...) that implies that mereological sums can change their parts). (shrink)

"Composition as identity" is the radical claim that the whole is identical to the parts - radical because it implies that a single object can be identical to many objects. Composition as identity, together with auxiliary assumptions, implies the principle of "collapse": an object is one of some things if and only it is part of the fusion of those things. Collapse has important implications: the comprehension principle of plural logic must be restricted, plural definite descriptions such as "the Cheerios (...) in the bowl" are empty, Composition as identity does not preclude emergent properties (contrary to what McDaniel has argued), and drastic simplifications of mereological and logical ideology are extensionally available. (shrink)