This research investigates relationships between philosophies and interior architecture, especially by analyzing the concept of space as the basic aesthetic unit of interior architecture from a philosophical point of view. The main focus has been developed on; space content, the contemporary form of space in everyday life, and the conceptual development of space by important philosophies and theories in the history of interior architecture. Research topics mainly consist of three theories; which are created by valuable architects and philosophers in the literature of interior architecture. These theories have been selected in order to focus on; space, spatiality, spatial relations, and spatial design. Starting with Beatriz Colomina’s (1994) ’Publicity and Privacy Architecture as Mass Media’, and the 2nd one is Le Corbusier’’s Plan Libre as; two contrasting inventions on space; introverted versus extroverted space characters. Lastly; the ’Visibility and Transparency in Architecture’ theory has been investigated by space relations to transform static spaces into dynamic spatiality. This flexible interior architecture has been examined by Van Doesburg’s Rietveld Schröder House