Canny and uncanny, like their German equivalents heimlich and unheimlich, have ambiguous double meanings. The relationship between canny, which means familiar, but also hidden threat, and uncanny which means unfamiliar, but strangely expected knowledge, is explored. The author proposes that the uncanny is derived from the reawakening of oedipal phantasies about parental coupling and the birth of siblings. He suggests that psychic growth requires toleration of the uncanny and free movement between it and canny states, corresponding with the oscillation between states, described by Bion, of Ps and D, where this promotes ‘Being’, through the realization of O. Childhood traumatic losses and oedipal anxieties can prevent this movement. This is illustrated by a woman who feared that the emergence of the uncanny would reveal her to be monstrous, through embodying her phantasy of being the ghost of her mother’s dead sister and the damaged child of her parents’ disastrous marriage. She was thus unable to allow this free movement and was condemned to ‘life on the margin’. This is contrasted with extracts from Wordsworth’s Prelude where ‘spots of time’, corresponding with screen memories, show how the liberation of the uncanny, and its free interchange with the canny, promotes mourning and growth.