Smallwood (2013) made important contributions to the science of mind wandering by distinguishing between 2 aspects of the mind-wandering experience: (a) "how" the mind wanders, which entails the "process" of maintaining the continuity of a mind-wandering episode, and (b) "why" the mind wanders, which refers to those mechanisms that lead to the "occurrence" of a mind-wandering episode. This new process-occurrence framework offers a way to compare and contrast existing theories of mind wandering and highlights key questions to be addressed in future work; however, we suggest that in characterizing one of the core mechanisms of mind wandering, Smallwood conflated the occurrence of a phenomenon with its explanation. Specifically, the occurrence of perceptual decoupling (i.e., that mind wandering is associated with reduced attention to external stimuli) was conflated with an explanation for its occurrence (i.e., in order to insulate the internal train of thought). Disentangling the theory of perceptual decoupling raises questions regarding both its role in insulating the internal train of thought in mind wandering and its unique theoretical contributions to the "how/process" of mind wandering. (Contains 1 footnote.)