Where Terence Penelhum sees a deep continuity between John Locke's theory of ideas and David Hume's theory of perceptions, I argue that the two philosophers disagree over some fundamental issues in the philosophy of mind. While Locke treats ideas as imagistic objects that we recognize as such by a special kind of inner consciousness, Hume thinks that we do not normally recognize the imagistic content of our perceptions, and instead unselfconsciously take ourselves to sense a shared public world. My disagreement (...) with Penelhum over Hume's debt to Locke helps to explain our disagreement over the nature of Hume's scepticism. (shrink)

This is a reply to Donald Ainslie's discussion of Terence Penelhum's work on Hume, Locke and the nature of consciousness; although agree on many points about the differences between Locke and Hume, I take issue with Ainslie's views about the epistemic status Hume accords to introspective acts.