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)