Manuel Fasko

This guide leads readers systematically through the arguments of Mary Shepherd's two books. Chapters 1-4 cover the arguments in the Essay Upon the Relation of Cause and Effect (1824), where Shepherd argues that causal principles can be known by reason to be necessary truths and that causal inferences can be rationally justified. Shepherd's primary target in this work is Hume, but she also addresses the views of Thomas Brown and William Lawrence. Shepherd considered her second book, Essays on the Perception of an External Universe, and Other Subjects Connected with the Doctrine of Causation (1827), to be an extension of the earlier project on causation; here she appeals to the causal principles established in the first book to argue that we can know through reason that an external world of continually-existing objects must exist independently of us, as the causes of our sensations. Chapter 5 of this Guide addresses Shepherd's accounts of sensation and reasoning; Chapters 6-9 lead the reader through the arguments of the Essays, as well laying out Shepherd's views on skepticism and Berkeleyan idealism, her accounts of mind and body, her philosophy of religion, and the solutions she offers to two puzzles about vision.

Berkeley's philosophy is meant to be a defense of commonsense. However, Berkeley's claim that the ultimate constituents of physical reality are fleeting, causally passive ideas appears to be radically at odds with commonsense. In particular, such a theory seems unable to account for the robust structure which commonsense (and Newtonian physics) takes the world to exhibit. The problem of structure, as I understand it, includes the problem of how qualities can be grouped by their co-occurrence in a single enduring object and how these enduring objects can bear spatiotemporal, causal, and other relations to one another. I argue that Berkeley's solution to these problems lies in his views about language. At one level, human language allows us to exploit patterns in our perceptions to construct a highly structured representation of the physical world which allows us to make accurate predictions at minimal cognitive expense. At a deeper level, these patterns occur in perception because our perceptions themselves form a language in which God speaks to us.