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The Metaphysics & Epistemology of Modality

Course Description

Modal notions are explicitly or implicitly involved in a massive variety of claims made in ordinary life, science, and philosophy. In particular, many of the central concepts of philosophy seem to lend themselves to a modal analysis – e.g., the concepts of free will, causation, dispositions, supervenience, logical consequence, and linguistic meaning, to name just a few. Further, the central concepts of ethics and epistemology are themselves expressed by modal auxiliaries in natural language (e.g. ought, should). So it seems that modality is central to all branches of philosophical inquiry. Yet modal notions give rise to a various philosophical puzzles: How are such notions to be analysed? In terms of possible worlds? If so, then what are these possible worlds? Are there even modal truths to be known? If there are, how do we gain knowledge of them? This course will explore these questions, introducing students to key topics regarding the metaphysics and epistemology of modality.

The first part of the course is an introduction to the metaphysics of modality. We will begin by looking at some of the reasons why possible worlds are theoretically useful, then examine a few different accounts of what possible worlds are. Topics will include realism about modality, Lewis’ realism about possible worlds, varieties of actualism, modalism, the de re/de dicto distinction, essentialism, counterpart theory, trans-world identity, and whether there are any contingent existents.

Meanwhile, the second part of the class covers epistemological issues regarding modality. Modal epistemology is particularly troubling because our ordinary methods for gaining knowledge – perception, inference, memory, & introspection – seem to give us no non-trivial modal knowledge. So the central challenge here is what Peacocke (1999) calls the ‘Integration challenge’ – namely, squaring a proposed account of what modal facts are with the possibility of our knowledge of such facts. Historically, the main view of how we can gain modal knowledge is that there is a connection between modal facts and some sort of mental activity (conceiving, imagining, or intuiting). The bulk of our investigation in the part will be examining this connection between possibility and conceivability. This will lead us to look at literature concerning the division of epistemic and metaphysical modalities, Two Dimensional Semantics, the relation between knowledge of counterfactuals and modal knowledge, and Bealer’s Modal Reliabilism.

Course Materials