The standard, foundationalist reading of Our Knowledge of the External World requires Russell to have a view of perceptual acquaintance that he demonstrably does not have. Russell’s actual purpose in “constructing” physical bodies out of sense-data is instead to show that psychology and physics are consistent. But how seriously engaged was Russell with actual psychology? I show that OKEW makes some non-trivial assumptions about the character of visual space, and I argue that he drew those assumptions from William James’s Principles. (...) This point helps us take a fresh look at the complex relationship between the two men. In light of this surprising background of agreement, I highlight ways their more general approaches to perception finally diverged in ways that put the two at epistemological odds. (shrink)

In ?155 of his New Theory of Vision Berkeley explains that a hypothetical ?unbodied spirit? ?cannot comprehend the manner wherein geometers describe a right line or circle?.1The reason for this, Berkeley continues, is that ?the rule and compass with their use being things of which it is impossible he should have any notion.? This reference to geometrical tools has led virtually all commentators to conclude that at least one reason why the unbodied spirit cannot have knowledge of plane geometry is (...) because it cannot manipulate a ruler or a compass. In this article I will show that such an interpretation is flawed. I will instead argue that Berkeley's understanding of Euclidian geometry was based on Isaac Barrow's account of the foundations of geometry. On this view geometrical objects are conceived in terms of the idealized motion that generates the objects of geometry. Consequently, that what the unbodied spirit cannot do in this context is to form an idea of motion rather than being unable to handle geometrical tools. 1All references to Berkeley are from, A. A. Luce and T. E. Jessop (eds.), The Works of George Berkeley, Bishop of Cloyne (London: Thomas Nelson and Sons, Ltd., 1948) The following abbreviations are used: An Essay Towards A New Theory of Vision, section x = New Theory x; Philosophical Commentaries, entry x = Commentaries x; Part I of A Treatise concerning the Principles of Knowledge, section x = Principles x. All other references to Berkeley's works are of the form The Works of George Berkeley, Bishop of Cloyne, volume x, page y = Works, x, y. (shrink)

Reid's Inquiry into the Human Mind on the Principles of Common Sense devotes more space to double vision than to any other topic. In what follows, I examine why this subject was so important to Reid and why he dealt with it as he did. I also consider whether his argument for his position begs the question against his main opponents, Berkeley and Robert Smith. I show that, as Reid presented it, it does, but that he could have said more (...) than he did in reply to Smith. My discussion of why double vision was important for Reid begins with an exposition of the relevance of the theory of vision for one of Reid's principal concerns in the Inquiry: the concern to respond to scepticism concerning our knowledge of an external world. I then turn to consider how Reid's account of double vision contributes to his epistemological realism and why the alternative account offered by Berkeley and Smith challenges it. (shrink)