Beauty has received sparse attention from emotion theorists, some of whom have argued that aesthetic pleasure is cognitive in nature and too “disinterested” to be emotional. This view is supported by research suggesting that aesthetic pleasure is based on processing fluency. The authors review recent findings in the psychology of aesthetics and present two arguments. First, processing fluency explains the mild pleasure associated with simple or familiar objects, but it cannot account for the more intense pleasure associated with complex or novel objects. Immediately recognizing an object tends to be mildly pleasant, whereas sensing the prospect of successfully representing a complex object can be exhilarating. Second, to explain how these forms of aesthetic pleasures differ, a theory must go beyond cognitive dynamics. The authors' affect-based model of emotion differentiates aesthetic pleasures in terms of epistemic goals. Pretty, fluently processed stimuli implicate prevention goals that maintain and protect knowledge. Beautiful, novel stimuli implicate promotion goals that reshape and expand knowledge. The emotional nature of interest and awe are also discussed.