A fair amount of the philosophical discussion about pain and unpleasantness has focused on providing a constitutive account of unpleasantness. These theories provide a more fundamental description of what unpleasantness is by appealing to other well-established notions in the architecture of the mind. In contrast, I address the nature of unpleasantness from a structural account. I will argue for how unpleasantness is built, rather than what unpleasantness is made of, as it were. I focus on the heterogeneity of experience, which (...) has been a somewhat neglected issue in the literature about unpleasantness: after careful introspection, there seems to be nothing phenomenal that all and only unpleasant experiences share. In order to address the heterogeneity of unpleasant experiences, I propose that the structure of the rich phenomenology of unpleasantness should be understood as a determinable property constituted by multiple essential dimensions. (shrink)