 Hallucination: if you visually hallucinate an oasis, you are not mistaken about something you see: prima facie, there is nothing to see. But even hallucinations seem to be perceptual awareness of something. Johnston (2004: 134f) therefore describes visual hallucinations as perceptual awareness of a complex property (he calls it a “profile”), a way some things might be, that is not instantiated (at the time).