Moten, Kaleb2019-09-202019-09-202019-05http://udspace.udel.edu/handle/19716/24459While there is broad consensus on the roles propositions can play (they are the bearers of truth values, meanings of sentences, and/or objects of beliefs and attitudes), there is far less consensus on their metaphysical nature. Some philosophers claims that propositions are sets of possible worlds. This thesis examines this claim with a particular focus on modal realism, the idea that these possible worlds are concrete entities of the same sort as the actual world. I examine two problems: first I determine whether sets of Lewisian worlds are the kind of objects we have epistemic access to, and if this alters their ability to take the propositional role. I then compare Lewisian propositions to their structured counterparts to determine if any other theories are more accurate at modeling content. I conclude that the structured propositional view of Jeffrey King solves many of the issue Lewisian propositions encounter while being conservative enough for a modal realist to adopt it with minimal sacrifices.Modal realismPhilosophyThesis