My topic in this paper will be Hume’s claim that we have no idea of a vacuum. I offer a novel interpretation of Hume’s account of our ideas of extension that makes it clear why those ideas cannot include any ideas of vacuums, and I distinguish my interpretation from prominent readings offered by other Hume scholars. An upshot of Hume’s account, I will argue, is his commitment to a remarkable and distinctly Humean view I call “perceptual relationism.” Perceptual relationism is (...) a fundamental characteristic of Hume’s “universe of the imagination,” and a manifestation of just how “loose and separate” the constituents of that inner universe are. Once we understand perceptual relationism and its entailments, we are in a better position to understand the rest of Hume’s sometimes puzzling remarks on space and the vacuum. (shrink)

I discuss the three distinctions “absolute and relative”, “true and apparent”, and “mathematical and common”, for the specific case of time in Newton’s Principia. I argue that all three distinctions are needed for the project of the Principia and can be understood within the context of that project without appeal to Newton’s wider metaphysical and theological commitments. I argue that, within the context of the Principia, the three claims that time is absolute rather than relative, true rather than apparent, and (...) mathematical rather than common, are to be evaluated with respect to the needs of, and relative to the success of, the project of the Principia. I claim that Newton is thereby offering a new, and empirical, philosophy of time. (shrink)