Realist positions about aesthetic properties are few and far between, though sometimes developed by analogy to realism about secondary properties such as colours. By contrast, I advance a novel realist position about aesthetic properties, which is based on a disanalogy between aesthetic properties and colours. Whereas colours are usually perceived as relatively steady features of external objects, aesthetic properties are perceived as unsteady properties: as powers that objects have to cause a certain experience in the observer. Following on from this observation, I develop a realist account of aesthetic properties as causally efficient powers. Beauty is not merely in the mind of the observer; it is a power of an object to bring about a cer...