Why might someone consider the answer to the titular question to be trivial? Perhaps because she has read some mereology and understands that mereologists distinguish between parthood on the one hand and proper parthood on the other. She understands that, at least when talking in the language of mereology, a thing is necessarily not a proper part of itself, but is necessarily a part of itself. Whether the English word “part” expresses parthood or proper parthood does not seem too important, (...) seeing as either can be taken as primitive and one defined in terms of the other. Thus, whether something is part of itself or not is indeed a trivial matter of definition. If by “part” one means parthood, everything is part of itself. If by “part” one means proper parthood, nothing is part of itself. (shrink)

Following Wiggins’ seminal article, On Being in the Same Place at the Same Time, this article presents the first comprehensive account of the relation of material constitution, an asymmetrical, transitive relation which totally orders distinct ‘entities’ (individuals, pluralities or masses of stuff) which ‘spatially coincide.’ Their coincidence in space is explained by a recursive definition of ‘complete-composition’, weaker than strict mereological indiscernibility, which also explains the variety of logically independent similarities in such cases. This account is ‘analytical’, dealing with ‘putative’ (...) cases in general. The main strategy is to rationally reconstruct Aristotle’s notion of material cause. It is developed more fully with a theory of how to justify admitting generable and perishable things into the natural world, in The Kinds of Things: A Theory of Personal Identity Based on Transcendental Argument (Open Court, 1996). (shrink)

This seems to me to be a metaphysically significant feature of CEM. If CEM is correct — if all its theorems are true, then metaphysicians have a choice to make in how we understand the mereological nature of the world. We may think of the mereological relation either as a relation of part to whole, or as a relation of overlap; for if we give a metaphysical theory about one, we thereby give a metaphysical theory about the other. We may (...) choose which we think of as more metaphysically fundamental, for the they are interdefinable. However, if CEM is not correct, then perhaps we do not have this choice. Perhaps part-whole cannot be defined in terms of overlap; in which case we must choose part-whole as the metaphysical fundamental mereological relation (if any relation is). (shrink)

The purpose of this paper is to examine how any domain of Meinongian objects can be structured by a special kind of mereology. The basic definition of this mereology is the following: an object is part of another iff every characteristic property of the former is also a characteristic property of the latter. I will show that this kind of mereology ends up being very powerful for dealing with Meinongian objects. Mereological sums and products are not restricted in any way (...) in a domain of Meinongian objects: there is a sum and a product for any pair of Meinongian objects. With the mereological operations of sum, product and complement, and two special Meinongian objects, we can define a full boolean algebra on Meinongian objects. Moreover, this kind of mereology is atomic and extensional: an atom is a Meinongian object having just one characteristic property and two objects are identical iff the same atoms are parts of both of them. A Meinongian object can finally be defined in mereological terms as the sum of the atoms of its characteristic properties. (shrink)

The properties, theoretical magnitudes, and natural kinds which science seeks to characterize, and not the sense or meanings which parts of speech may possess, are the subject of this paper. Many philosophers (e.g., Putnam [1971] and Achinstein [1974]) have agreed that two predicates of different meaning may pick out the same property, but they usually hold that that logically equivalent predicates must pick out the same properties. I propose to deny this thesis. My argument is by way of an example (...) and by appeal to a principle. The principle connects propertyhood with causal efficacy. The example situation I will describe in what follows is intended to show that the property of being a closed straight-sided figure having three sides is not the same property as that of being a closed straight-sided figure having three angles (a triangle). (shrink)

in D. Dieks (ed.), The Ontology of Spacetime, Vol. 2. Elsevier, forthcoming.

Quine said that the ontological question can be asked in three words, ‘What is there?’, and answered in one, ‘everything’. He was wrong. We need an extra word to ask the ontological question: it is ‘What is there, really?’; and it cannot be answered truthfully with ‘everything’ because there are some things that exist but which don’t really exist (and maybe even some things that really exist but which don’t exist).

This paper investigates the relation of the Calculus of Individuals presented by Henry S. Leonard and Nelson Goodman in their joint paper, and an earlier version of it, the so-called Calculus of Singular Terms, introduced by Leonard in his Ph.D. dissertation thesis Singular Terms. The latter calculus is shown to be a proper subsystem of the former. Further, Leonard’s projected extension of his system is described, and the definition of an intensional part-relation in his system is proposed. The final section (...) discusses to what extend Goodman might have contributed to the formulation of the Calculus of Individuals. (shrink)

A set of parameters for classifying composition operations is introduced. These parameters determine whether a composition operation is 1) universal, 2) determinate, 3) whether there is a difference between possible and actual compositions, 4) whether there can be singleton compositions, 5) whether they give rise to a hierarchy, and 6) whether components of compositions can be repeated. Philosophical implications of these parameters (in particular in relation to set theory) and mereology are discussed.