•  752
    This paper provides an axiomatic formalization of a theory of foundational relations between three categories of entities: individuals, universals, and collections. We deal with a variety of relations between entities in these categories, including the is-a relation among universals and the part-of relation among individuals as well as cross-category relations such as instance-of, member-of, and partition-of. We show that an adequate understanding of the formal properties of such relations – in …Read more
  •  441
    Endurantist and perdurantist accounts of persistence
    Philosophical Studies 154 (1). 2011.
    In this paper, I focus on three issues intertwined in current debates between endurantists and perdurantists—(i) the dimension of persisting objects, (ii) whether persisting objects have timeless, or only time-relative, parts, and (iii) whether persisting objects have proper temporal parts. I argue that one standard endurantist position on the first issue is compatible with standard perdurantist positions on parthood and temporal parts. I further argue that different accounts of persistence depe…Read more
  •  262
    Standard theories in mereotopology focus on relations of parthood and connection among spatial or spatio-temporal regions. Objects or processes which might be located in such regions are not normally directly treated in such theories. At best, they are simulated via appeal to distributions of attributes across the regions occupied or by functions from times to regions. The present paper offers a richer framework, in which it is possible to represent directly the relations between entities of var…Read more
  •  213
    We propose an ontological theory that is powerful enough to describe both complex spatio-temporal processes and the enduring entities that participate therein. For this purpose we introduce the notion a directly depicting ontology. Directly depicting ontologies are based on relatively simple languages and fall into two major categories: ontologies of type SPAN and ontologies of type SNAP. These represent two complementary perspectives on reality and employ distinct though compatible systems of c…Read more
  •  202
    It is often assumed that indeterminacy in mereological relations—in particular, indeterminacy in which collections of objects have fusions—leads immediately to indeterminacy in what objects there are in the world. This assumption is generally taken as a reason for rejecting mereological vagueness. The purpose of this paper is to examine the link between mereological vagueness and existential vagueness. I hope to show that the connection between the two forms of vagueness is not nearly so clear-c…Read more
  •  117
    Using mereological principles to support metaphysics
    Philosophical Quarterly 61 (243): 225-246. 2011.
    Mereological principles are sometimes used to support general claims about the structure and arrangement of objects in the world. I focus initially on one such mereological principle, the weak supplementation principle (WSP). It is not obvious that (WSP) is prescribed by ordinary thinking about parthood. Further, (WSP) is not needed for a fairly strong formal characterization of the part–whole relation. For these reasons, some arguments relying on (WSP) might be countered by simply denying (WSP)…Read more
  •  103
    In R. Holte and A. Howe (eds.), Proceedings of the Twenty-Second AAAI Conference on Artificial Intelligence (AAAI-07).
  •  85
    Summation relations and portions of stuff
    Philosophical Studies 143 (2). 2009.
    According to the prevalent 'sum view' of stuffs, each portion of stuff is a mereological sum of its subportions. The purpose of this paper is to re-examine the sum view in the light of a modal temporal mereology which distinguishes between different varieties of summation relations. While admitting David Barnett's recent counter-example to the sum view, we show that there is nonetheless an important sense in which all portions of stuff are sums of their subportions. We use our summation relation…Read more
  •  75
    The theory of granular partitions is designed to capture in a formal framework important aspects of the selective character of common-sense views of reality. It comprehends not merely the ways in which we can view reality by conceiving its objects as gathered together not merely into sets, but also into wholes of various kinds, partitioned into parts at various levels of granularity. We here represent granular partitions as triples consisting of a rooted tree structure as first component, a doma…Read more
  •  38
    Relative places
    Applied ontology 1 (1): 55-75. 2005.
    Newton distinguishes between absolute and relative places. Both types of places endure through time and may be occupied by various objects at various times. But unlike absolute places, each relative place stands in fixed spatial relations with one or more reference objects. Relative plac-es with independent reference objects (e.g. a ship and the earth) may move relative to one another. Relative places, not absolute places, are used to locate objects and track their movements in common-sense re…Read more
  •  29
    The Cognitive Value of Literary Perspectives
    Journal of Aesthetics and Art Criticism 77 (1): 11-22. 2019.
  •  24
    Non-symmetric relations like loves or between can apply to the same relata in non-equivalent ways. For example, loves may apply to Abelard and Eloise either by Abelard’s loving Eloise or by Eloise’s loving Abelard. On the standard account of relations, different applications of a relation to fixed relata are distinguished by the direction in which the relation applies to the relata. But neither Directionalism nor its most popular rival, Positionalism, offer accounts of differential application t…Read more
  •  4
    Parthood and Multi-location
    Oxford Studies in Metaphysics 5 203-243. 2010.
  •  3
    A formal theory for reasoning about parthood, connection, and location
    Artificial Intelligence 160 (1-2): 145-172. 2004.
    In fields such as medicine, geography, and mechanics, spatial reasoning involves reasoning about entities that may coincide without overlapping. Some examples are: cavities and invading particles, passageways and valves, geographic regions and tropical storms. The purpose of this paper is to develop a formal theory of spatial relations for domains that include coincident entities. The core of the theory is a clear distinction between mereotopological relations, such as parthood and connection, a…Read more
  •  1
    Formal Ontology and Information Systems (edited book)
    with Giancarlo Guizzardi
    IOS. 2012.
  • An Axiomatization of Common-Sense Geometry
    Dissertation, The University of Texas at Austin. 2001.
    We organize things and places in our world according to spatial relations such as ...is next to..., ...is close to..., ...is above..., ... is to the right of..., ...is twice as far from ...as from..., and ...is three feet from.... These concepts range from the qualitative, imprecise, and context-dependent to the quantitative, precise, and context-independent . They are logically inter-related in the following sense. If we know that a pair of objects satisfies one of these relations, then we can …Read more