I Dream Therefore I Am: A Review On Lucid Dreaming In Western Philosophy

The first philosopher who referred to lucid dreaming (LD) was Aristotle, who pointed out that something in the dreamers' consciousness tells them they are dreaming. In the Middle Ages, Aquinas commented that while asleep a man may judge that what he sees is a dream. During enlightenment, Reid alleged that he experienced waking-like cognition during dreams. In the 19th century, Nietzsche mentioned that he sometimes would realize he was dreaming amid a nightmare. In the past century, new arguments were given against the arising of self-consciousness in dreams. Malcolm, for example, based on the incapacity of communicating with the external world during the dream, concluded for the impossibility of a genuine dream "experience"-which would preclude LD. In the 1970s, there was a brief discussion between Dennett, for whom dreams are not experiences, and Emmett, who rebutted his argument citing LD, followed by Dennett's reply that LDs are merely "illusions of a dream within a dream." In 1981, the psychophysiologist LaBerge and coworkers recorded LD in the laboratory, which proved scientifically the existence of LD. Nowadays, many philosophers consider dreams as a key phenomenon for the study of consciousness and the mind-body problem, such as Antti Revonsuo, Jennifer Windt, Evan Thompson, and Thomas Metzinger, who agree that LD presents cognitive functions like self-consciousness. In this review, we explore these and other Western thinkers who wrote about LD throughout history.