This paper aims to clarify Locke’s distinction between simple and complex ideas. I argue that Locke accepts what I call the “compositional criterion of simplicity.” According to this criterion, an idea is simple just in case it does not have another idea as a proper part. This criterion is prima facie inconsistent with Locke’s view that there are simple ideas of extension. This objection was presented to Locke by his French translator, Pierre Coste, on behalf of Jean Barbeyrac. Locke responded (...) to Barbeyrac’s objection, but his response, along with a passage from Chapter XV of Book II of the Essay, “Of Duration and Expansion, considered together,” has been taken to show that he did not accept the compositional criterion. I examine these passages and argue that they are not in tension with but rather affirm that criterion. (shrink)

Locke seems to hold that we have knowledge of the existence of external objects through sensation. Two problems face Locke's account. The first problem concerns the logical form of knowledge of real existence. Locke defines knowledge as the perception of the agreement or disagreement between ideas. However, perceiving agreements between ideas seems to yield knowledge only of analytic truths, not propositions about existence. The second problem concerns the epistemic status of sensitive knowledge: How could the senses yield certain knowledge? This (...) essay argues that the key to solving both problems is Locke's claim that simple ideas are all real, adequate, and true. This explains why, on Locke's view, we have certain knowledge through the senses. It also explains how sensitive knowledge can consist in perceiving an agreement between ideas: perceived agreements among simple ideas of sensation are guaranteed to track relations that obtain among really existing things. (shrink)

This paper offers an epistemic defense of empathy, drawing on John Locke's theory of ideas. Locke held that ideas of shape, unlike ideas of color, had a distinctive value: resembling qualities in their objects. I argue that the same is true of empathy, as when someone is pained by someone's pain. This means that empathy has the same epistemic value or objectivity that Locke and other early modern philosophers assigned to veridical perceptions of shape. For this to hold, pain and (...) pleasure must be a primary quality of the mind, just as shape is a primary quality of bodies. Though Locke did not make that claim, I argue that pain and pleasure satisfy his criteria for primary qualities. I consider several objections to the analogy between empathy and shape-perception and show how Locke's theory has resources for answering them. In addition, the claim that empathetic ideas are object-matching sidesteps Berkeley's influential objection to Locke's theory of resemblance. I conclude by briefly considering the prospects for a similar defense of empathy in contemporary terms. (shrink)

Locke defines knowledge as the perception of the agreement or disagreement of ideas. Nevertheless, he claims that we know particular things: the identity of our ideas, our own existence, and the existence of external objects. Although much has been done to reconcile the definition of knowledge with our knowledge of external objects, there is virtually nothing in the scholarship when it comes to knowing ideas or our own existence. I fill in this gap by arguing that perceptions of ideas are (...) complex mental states that convey propositional knowledge due to agreeing elements therein. (shrink)