Abstract: As a number of commentators have noted, Margaret Cavendish's relationship with philosophical skepticism is a somewhat contentious subject. On the one hand, Cavendish has been variously understood as a "modest skeptic" (Deborah Boyle), a proponent of a domain-specific "extreme" skepticism regarding knowledge of nature's inner workings (Lisa Sarasohn), and a proponent of a broader "extreme" skepticism about knowledge in general (Anna Battigelli). On the other hand, Cavendish never explicitly proclaims herself to be a skeptic of any sort, and some recent attempts at offering a systematic account of Cavendish's epistemology (such as those of Kourken Michaelian and Colin Chamberlain) leave no room for anything which might be plausibly construed as skepticism.

The puzzling lack of agreement among scholars regarding skepticism's place in Cavendish's philosophical system may be in part attributable to subtle discrepancies between her stated views on knowledge, certainty, and probable opinion in her Observations upon Experimental Philosophy, her Philosophical Letters, and her Grounds of Natural Philosophy. This paper aims to render these three consistent with one another, offering an account which bridges the gap between her fallibilistic but apparently non-skeptical epistemology in the Observations upon Experimental Philosophy with decidedly less optimistic remarks about the possibility of knowledge in her other mature works.

The reconstruction of Cavendish's epistemology offered here renders Cavendish as a proponent of an unusual form of skepticism; namely, one which denies the possibility of certain knowledge, affirms that we form probable opinions about the world, affirms that highly probable opinions might indeed sometimes constitute a lesser degree of knowledge, but further denies that we can aspire to even this lesser degree of knowledge in most domains. While this may initially seem to be incompatible with Cavendish's endeavors in natural philosophy, I argue that she often uses the term "knowledge" in reference to merely probable opinions which do not amount to knowledge but which we are entitled to provisionally treat as knowledge. While her seemingly non-skeptical fallibilism thus ends up amounting to a variety of "extreme skepticism" in most domains, I contend that this does not render the search for mere probable opinion any less important for Cavendish, and that it is therefore possible to see her as both a staunch advocate for inquiry regarding the true natures of things and an ardent skeptic about the possibility of uncovering genuine knowledge about them.