The study lies within in the realm of architectural theory and considers the ontology of interior design by investigating the marginalisation of the discipline within the architectural profession. The discipline is personified and placed in a dialectic relationship with architecture. This enables the researcher to disengage interior design from architecture and, by stating the disciplines as ‘absolute Others’ the researcher is allowed to essentialise the disciplines in question. The research was conducted with a liberal plural meta-theoretical approach and can best be described as a heuristic enquiry. In this situation neither the objective realm, nor the researcher’s subjectivity is the primary focus. Literature studies were employed to identify relevant architectural theories to supply the necessary empirical material. The dissertation is presented as object-relations oriented criticism and follows a subversive strategy to allow the researcher to inscribe his self-identification as an interior designer. The findings are presented as a negative depiction of the status quo. This can be summarised as a situation where the existence of a dialectic opposite pair (‘interior design’: ‘architecture’) is the main obstacle in the establishment of a discrete identity for interior design. The dialectic pair is deconstructed to allow interior design to form its own identity without reference to architecture. The study concludes that interior design and architecture are not separate professions, since they are unable to establish discrete, autonomous fields of knowledge; they are, however, distinct disciplines or ‘branches of learning’. The study defines interior design as a mode of cultural production which engages in the design of enclosed spaces in existing structures, with emphasis on the design of volume. In addition, the study proposes the creation of a single architectural profession to contain the architectural disciplines.