This thesis attempts to extend the scope of consideration of the pre-oedipal or pre- symbolic mother-infant relationship by focusing on a 'third' space that exists between them, and the remains of this space in the infant's unconscious. Through the theoretical explication of two non-concepts, the "third aesthetic" and the "O- Function", the thesis endeavours to develop a framework, from a psychoanalytic perspective, which considers how the inauguration of a trace is established so that the infant may seek out or create meaning at a later stage of life following maturation or individuation. The thesis has not however insisted on defining the construct of meaning per se, which is invariably a subjective and existential endeavour or idiom, but is rather concerned with what may provide a possibility for subsequent meaning- making endeavours. The notion of a third space, which alludes to a meeting point of two subjectivities which in turn proliferates a third arena of negotiation, considers other (lirninal) spatial and temporal possibilities that exist (or rather ex-sist) between the mother and the infant. This third time-space (the "third aesthetic"), which takes its cue from "chora/khdra" (as explored by Plato, Julia Kristeva and Jacques Derrida) and the "potential space" (as identified by the psychoanalyst D.W. Winnicott), is developed through a consideration of thirdness (or more specifically thirdness under erasure, and the refusal to enclose it within a triad), the aesthetic, metaphor and metonymy, and rhythm. What remains of this third energetic body in the infant's unconscious (the "O-Function") is considered through the tropes of the trace, the gift and cinders, as well as through the ineluctably uncanny rhythms of desistance (of the future-to-come). The thesis focuses critically on what tropological or metaphoric forums may be provided in service of explicating these two 'non-concept' concepts given the problematics of representation.