 A number of researchers have begun to consider dreaming in the context of theories of mind wandering. Mind wandering is frequent in waking and involves spontaneous thoughts that unfold dynamically and are only weakly constrained by ongoing tasks and environmental demands (Schooler et al. 2011; Smallwood &amp; Schooler 2015; Christoff et al. 2016). Based on phenomenological and neurophysiological similarities, dreams have been proposed to be an intensified form of waking mind wandering (Pace-Schott 2007, 2013; Domhoff 2011; Wamsley 2013; Fox et al. 2013). This basic idea seems to have been anticipated by Leibniz, who noted that the spontaneous formation of visions in dreams surpasses the capacity of our waking imagination (Leibniz, Philosophical Papers and Letters, Vol. I, 177–178).