 Malcolm argued that retrospective dream reports are the sole criterion for determining whether a dream occurred and there is no independent way of verifying dream reports. While first-person, past-tense psychological statements (such as “I felt afraid”) can at least in principle be verified by independent observations (but see Canfield 1961; Siegler 1967; Schröder 1997), he argued dream reports (such as “in my dream, I felt afraid”) are governed by different grammars and merely superficially resemble waking reports. In particular, he denied dream reports imply the occurrence of experiences (such as thoughts, feelings, or judgements) in sleep: