This paper aims to answer the question: Which conception of the self should we be informed by, if we want to understand the true essence of the self as well as architecture? To this end, I criticize the architectural theories that have been dominantly inspired by Heidegger’s phenomenological approach, suggesting that those who regard architecture as a morphological concept that has been defined and determined by the context in which it appears overlook the significance of the negation process, active agency and consciousness of being. Those scholars who overly focus on human relation to space also underestimate the human relation to self. These aspects of self are respectively discussed in reference to the modernist, post-modernist and biological architecture. The paper concludes in agreement with Susan Herrington that “an explanation of its materials, mode of production and representations cannot account for an ontology of [architecture]” (2008:62). If we want to understand the true essence of the self and architecture we have to be informed by Sartre’s philosophical approach that conceptualizes the self as an active agent whose existence cannot be preceded by essence.