“Affect” names a conceptual problem as much as a tangible thing. As such, it is best understood as an umbrella term that includes related, and more familiar, words such as “feeling” and “emotion,” as well as efforts to make distinctions among them. The Oxford English Dictionary (OED) traces the history of the term to the seventeenth century, aligning it with “desire” or “passion” and opposing it to “reason.” Further specifying that “affect” is both a “mental” and a “bodily” disposition, the OED sets in place a persistent ambiguity that challenges distinctions between mind and body. More technical uses of the term emerge from mid-twentieth-century scientific psychology, where “affect” designates sensory processes or experiences prior to cognition and distinguishes such sensations from the cognitive processes that produce emotions (Damasio 1994). Because affect, emotions, and feelings stand at the intersection of mind and body, cognition and sensation, and conscious and unconscious or autonomic processes, it is not easy to identify the material basis for their social and historical construction, which includes parts of the body (nerves, brains, or guts) as well as environments and transpersonal relations.