The metaphysical explanation of modal and non-modal truths

Abstract In this paper I discuss an initially very plausible principle about metaphysical explanation, which has recently been explicitly defended. Suppose some q metaphysically explains the metaphysical necessity of p . Does q then also metaphysically explain p ’s truth? The principle at issue, call it ‘(NT)’, gives an affirmative answer to that question. I show that (NT), if true, has widespread consequences concerning the metaphysics of modality, of fundamentality, and the debate about metaphysical explanation. Most importantly, under some plausible assumptions, (NT) would render a plethora of well-established views in modal metaphysics plainly false. Luckily, however, despite its initial plausibility, (NT) fails as a general principle about metaphysical explanation. I shall argue that the three discussed general arguments for (NT) all fail, that the specific arguments in its favor all depend on very specific (and, arguably, contentious) metaphysical views on the source of modality, and that (NT) is indeed incompatible with other (arguably less contentious) metaphysical views concerning modality.