On its face, Hume's account of mental representation involves at least two elements. On the one hand, Hume often seems to write as though the representational properties of an idea are fixed solely by what it is a copy or image of. But, on the other, Hume's treatment of abstract ideas (and other similar cases) makes it clear that the representational properties of a Humean idea sometimes depend, not just on what it is copied from, but also on the manner in which the mind associates it with other ideas. Past interpretations of Hume have tended to focus on one of these elements of his account to the neglect of the other. But no interpretation of this sort is likely to capture the role that both copying and association play within Hume's discussion. In what follows, I argue that the most plausible way of understanding Hume's discussion involves attributing to him a unified account of mental representation in which both of these elements play a central role. I close by discussing the manner in which reading Hume in this way would alter our understanding of the relationship between Hume's thought and contemporary philosophy of mind.