Abstract

I examine Amie Thomasson’s account of the metaphysics of mountains and their boundaries, from her “Geographic Objects and the Science of Geography.” I begin by laying out a puzzle about mountains that generates some pressure towards accepting that we are somehow responsible for their having the boundaries that they do. As a foil for Thomasson’s own account, I present two competing theories of geographic objects—one on which they are thoroughly mind-dependent, and one on which they are thoroughly mind-independent—neither of which yields a fully satisfying solution to the puzzle. I then turn to Thomasson’s intriguing suggestion that, although the geographic objects themselves are mind-independent, the boundaries of those objects are not. Finally, I examine whether Thomasson’s account is equipped to solve the puzzle, and I explore how her account interacts with her plenitudinous ontology.