4. Categories of Being
4.1 Introduction
A central task ofontologyis to discover the correct list ofontological categories.
A central task ofmeta-ontologyis to determinewhat it is to be an ontological category
andwhat it is to fall under an ontological category.^1 Here I explore a traditional meta-
ontology in which ontological categories areways of beingand objects belong to the
same ontological category just in case theyexist in the same way.
Why engage in the project of defining“ontological category”? First, as Jan
Westerhoff (2005: 22–4) notes, if we don’t know what ontological categories are,
we don’t know what ontologists are supposed to be looking for. As Gilbert Ryle
(1971: 170) elegantly stated,“We are in the dark about the nature of philosophical
problems and methods if we are in the dark about types or categories.”
Moreover, the notion of an ontological category is theoretically useful only to the
extent that itcan beemployed inprinciplesthat make use ofit. But such principleswillbe
unclear as long as the notion of an ontological category is unclear. I’dliketouseaclear
notion of an ontological category to help me think through issues in the metaphysics of
modality (construed broadly) and essence (construed narrowly). More on this shortly.
“Ontological category”is a philosopher’s term of art, not a bit of ordinary language.
There are two kinds of projects one might mean by the phrase“providing an account of
ontological categories.”Thefirst kind of project is the historical or hermeneutical
project of determining what some philosopher or philosophers meant by“ontological
category”—or simply“category”—and then determining the roles that their particular
conceptions of what it is to be an ontological category played in their theorizing. The
second is the metaphysical project of determining what philosophersoughtto mean by
“ontological category”by arguing that a particular (and perhaps somewhat stipulative)
account tracks something that ontologists ought to care about.
My focus will be on the second project, although as it will turn out, I think
sensitivity to thefirst project is important for success in the second. And, in general,
(^1) Lowe (2006: 34) says that any system of ontology must determine what ontological categories are, and
says (2006: 69) thatformal ontologyis the branch of metaphysics whose job it is to do this. (I use“formal
ontology”in a different way in section 4.6.) I follow van Inwagen (2001b) and Westerhoff (2005) in
distinguishing between meta-ontological questions andfirst-order ontological questions, which Westerhoff
(2005: 20–1) calls“object-level ontological questions.”