 It should be noted, however, that things are more complex than the earlier remarks of Hume and Maxwell suggest. Descartes and Locke, for example, think that there are no colors in the physical world—no colors, as we ordinarily and naively understand them to be. But they are also widely interpreted as holding a secondary quality view of colors, i.e., holding the view that colors are powers or dispositions to cause experiences of a certain type. It is instructive to try to understand this dual position. We find, for example, this passage in Descartes’ Principles of Philosophy: