One More Angel in Heaven: Modal Plenitude and Paradox

Philosophy of Science Colloquium
The Institute Vienna Circle holds a Philosophy of Science Colloquium with talks by our present fellows.

Date: 14/12/2023

Time: 15h00

Venue: New Institute Building (NIG), Universitätsstraße 7, 1010 Wien, SR 2H

Abstract:

It is natural to assume that what is metaphysically possible is closed under certain principles of plenitude. These are principles to the effect that if such and such is metaphysically possible, then such and so ought to be metaphysically possible as well. For instance, assuming that it is possible in the relevant sense for there to be an angel, then it should be possible for there to be this angel as well as another one distinct from it. Principles of plenitude delimit the scope of metaphysical possibility, so to speak. A modal paradox due to Fritz (2017) shows that plausible principles of plenitude for metaphysical possibility are mutually inconsistent. I present one solution to the paradox according to which metaphysical modality exhibits a kind of indefinite extensibility (Roberts, 2019; Rayo, 2020). Roughly, this is the view that for any objective notion of possibility, a more inclusive notion can be defined. This means that there are many possible interpretations of the metaphysical "could", each taking a different opinion on whether something could have been the case. I outline my preferred way of spelling out this conception of metaphysical modality and explore its consequences for modal metaphysics.