Does a commitment to mereological universalism automatically bring along a commitment to the controversial doctrine of mereological extensionalism—the view that objects with the same proper parts are identical? A recent argument suggests the answer is ‘yes’. This paper attempts a systematic response to the argument, considering nearly every available line of reply. It argues that only one approach—the mutual parts view—can yield a viable mereology where universalism does not entail extensionalism.

The connection between whole and part is intimate: not only can we share the same space, but I’m incapable of leaving my parts behind; settle the nonmereological facts and you thereby settle what is a part of what; wholes don’t seem to be an additional ontological commitment over their parts. Composition as identity promises to explain this intimacy. But it threatens to make the connection too intimate, for surely the parts could have made a different whole and the whole have (...) had different parts. In this paper I attempt to offer an account of parthood that is intimate enough but not too intimate: the parts generate the whole, but they are not themselves the whole. (shrink)

Consider a circle and a pair of its semicircles. Which is prior, the whole or its parts? Are the semicircles dependent abstractions from their whole, or is the circle a derivative construction from its parts? Now in place of the circle consider the entire cosmos (the ultimate concrete whole), and in place of the pair of semicircles consider the myriad particles (the ultimate concrete parts). Which if either is ultimately prior, the one ultimate whole or its many ultimate parts?

Thinking about space is thinking about spatial things. The table is on the carpet; hence the carpet is under the table. The vase is in the box; hence the box is not in the vase. But what does it mean for an object to be somewhere? How are objects tied to the space they occupy? This book is concerned with these and other fundamental issues in the philosophy of spatial representation. Our starting point is an analysis of the interplay between (...) mereology (the study of part/whole relations), topology (the study of spatial continuity and compactness), and the theory of spatial location proper. This leads to a unified framework for spatial representation understood quite broadly as a theory of the representation of spatial entities. The framework is then tested against some classical metaphysical questions such as: Are parts essential to their wholes? Is spatial colocation a sufficient criterion of identity? What (if anything) distinguishes material objects from events and other spatial entities? The concluding chapters deal with applications to topics as diverse as the logical analysis of movement and the semantics of maps. (shrink)

The objects we encounter in ordinary life and scientific practice - cars, trees, people, houses, molecules, galaxies, and the like - have long been a fruitful source of perplexity for metaphysicians. The Structure of Objects gives an original analysis of those material objects to which we take ourselves to be committed in our ordinary, scientifically informed discourse. Koslicki focuses on material objects in particular, or, as metaphysicians like to call them "concrete particulars", i.e., objects which occupy a single region of (...) space-time at each time at which they exist and which have a certain range of properties that go along with space-occupancy, such as weight, shape, color, texture, and temperature. The Structure of Objects focuses in particular on the question of how the parts of such objects, assuming that they have parts, are related to the wholes which they compose. (shrink)

'Ontological dependence' is a term of philosophical jargon which stands for a rich family of properties and relations, often taken to be among the most fundamental ontological properties and relations. Notions of ontological dependence are usually thought of as 'carving reality at its ontological joints', and as marking certain forms of ontological 'non-self-sufficiency'. The use of notions of dependence goes back as far as Aristotle's characterization of substances, and these notions are still widely used to characterize other concepts and to (...) formulate metaphysical claims. This paper first gives an overview of the varieties of these notions, and then discusses some of their main applications. (shrink)

I argue that Universalism (the thesis that mereological composition is unrestricted) entails Extensionalism (the thesis that sameness of composition is sufficient for identity) as long as the parthood relation is transitive and satisfies the Weak Supplementation principle (to the effect that whenever a thing has a proper part, it has another part disjoint from the first).

In a recent article in this journal, Achille Varzi (2009) argues that mereological universalism (U) entails mereological extensionalism (E). The thesis that U entails E (call it ‘T’) has important implications. For example, as is well known, T plays a crucial role in Peter van Inwagen’s argument against universalism (1990: 74–79). In what follows, I show that Varzi’s arguments for T rely on a tendentious assumption about parthood.