Abstract
In what follows, I argue that Hume works with a notion of the a priori that, though unfamiliar today, was standard in the seventeenth and eighteenth centuries. On this notion of the a priori, to know (consider, prove) something a priori is to know (consider, prove) it from the grounds that make it true. I will refer to this as the "from-grounds" notion of the a priori, and to the now-familiar and dominant notion—on which to know something a priori is to know it with a justification that is independent of experience—as the "non-empirical" notion.Hume holds, as a substantive thesis, that one knows something a priori, where 'a priori' is understood in the from-grounds sense, only if one knows it independently of ..