The idea of the third which appears in Jung's concepts of the transcendent function and the coniunctio also occurs in several psychoanalytic theories concerning the emergence of reflective and symbolic thought in childhood development (defined here as the development of ‘imaginal capacity’). Noting the way this process is often conceived in terms of the metaphor of sexual intercourse leading to ‘conception’, this paper suggests that such images need to be understood as symbolic conceptions of the meaning-making functions of the human mind. This leads to a different view of psychoanalytic theories that attempt to account for the development of imaginal capacity in terms of the Oedipus complex. It is suggested that a) these functions must be operative in the mind before the Oedipal situation can become meaningful and b) that psychoanalytic theories are themselves symbolic conceptions which, like mythological narratives, seek to communicate and comprehend psychic reality through imaginal forms.