Ontological Categories, Existence Statements, and Metaphysical Modality

What is the content of the claim that tropes a and b are co-instantiated if there is no such thing as tropes? I begin this thesis by arguing that a sentence expressing such a claim would be deficient in content and would, therefore, not be truth-apt. I use this claim to set up a general presupposition problem for the truth-apt sentences of our language. I argue that all truth-apt sentences presuppose the existence of the kinds of things which are to serve as the semantic values of their terms. Understanding the content of such a presupposition requires understanding the content of a categorial existence claim. However, I argue, it is incredibly difficult to provide a construal of categorial existence claims which does not presuppose the existence of the very things that they would be used to assert the existence of. I argue that to provide a satisfactory construal, we need to appeal to the notion of an ontological category. I contend that the notion of an ontological category with which we can provide a satisfactory construal of existence claims is a broadly Lowean one. I show that, as it stands, Lowe’s construal is not adequate to the task but that it can be modified so that it is. Making use of such a modified construal, I defend a metalinguistic construal of categorial existence claims. In chapters five and six, I argue that if we fully appreciate the notion of an ontological category which has been introduced, the notion of that which I claimed we have to make use in answering the question of ontology and referring to things in the world, we will recognise that such ontological categories ground, or partially ground, de re modal truths, and through them, the truths of metaphysical modality.