Winnicott's theory is based on the assumption that the infant and maternal caretogether form a unit. According to Winnicott, the transitional object represents the early stages of the use of illusion and in this respect, the mother's ability to present the world in such a way that the infant does not at first have to know that the object is not created by the infant. Winnicott's notion of the creation of the subject in the potential space between the infant and mother involves dialectical relationship in the period of development in which transitional phenomena occur. The development of the capacity to be alone, as an experience of being alone in the presence of the mother, is a process in which the mother's role is taken over by the child in the course of gradual weaning of the infant from maternal provision of the holding environment. Winnicott's conception of the subject represents one of the cornerstones of psychoanalytic theory.