 Hume was less clear on this matter, proposing that dreams occupy an intermediate position between vivid and largely non-voluntary sensory impressions and ideas, or “the faint images of previous impressions in thinking and reasoning” (Hume 1739: 1.1.1.1). On the one hand, as mere creatures of the mind, Hume wanted to categorize dreams as ideas. On the other hand, he acknowledged that in sleep, “our ideas can approach the vivacity of sensory impressions” (Hume 1739: 1.1.1.1). Dreams do not fit comfortably into Hume’s attempt to draw a dichotomous distinction between impressions, including perception, and ideas, including sensory imagination (Ryle 1949; Waxman 1994; Broughton 2006).