Abstract
ABSTRACT According to an important version of the Principle of Sufficient Reason, every fact has a metaphysical explanation, where a metaphysical explanation of some fact tells us what makes it the case that the fact obtains. I argue that, so long as we have not yet discovered that any fact is brute, we ought to be committed to this version of the principle—henceforth ‘the PSR’—because it is indispensable to a species of inquiry in which we ought to engage. I argue, first, that a practical indispensability argument applied to this species of inquiry supports a commitment to the PSR. I then show that we ought to engage in this inquiry. If my argument succeeds, then our attitude at the outset of such inquiry should not be agnosticism about whether any particular fact has a metaphysical explanation. Instead, we ought to be committed to the PSR.