Ontology is the most general science or study of Being, Existence, or Reality. An informal use of the term signifies what, in general terms, a philosopher considers the world to contain. Thus it is said that Descartes proposed a dualist ontology, or that there were no gods in d'Holbach's ontology. But in its more formal meaning, ontology is the aspect of metaphysics aiming to characterize Reality by identifying all its essential categories and setting forth the relations among them.

Being Qua Being

Existence, as the most comprehensive category of all, should embrace members with the least in common. Nevertheless, Western philosophy long sought some substantive common content present in anything just in virtue of its existence. The history of these attempts to identify the common character of being qua being is not encouraging.

In The Sophist, Plato's Eleatic Stranger proposes that a role in the world's causal network...