In many publications and conferences on the subject, it is not unusual to hear the interior described as a slippery subject (Hollis 2007: Edwards 2011: Rogers 2012). This aspect of fluidity can, for some, be a source of unease, and sometimes can provide all too easy assumptions regarding a possible deficiency of an intellectual veracity in the subject. I would like to make it clear thus I begin this paper from the position that this fluid quality is actually the raison d’être of the subject. Put simply, I consider it to be one of the underlying principles and fundamental conditions of the interior. What I mean by this is that anybody, any agent working in this field is of a sensibility that revels in the ambiguity and unfixedness of the subject of the interior. Therefore, in this paper, it is taken as read that spatial, critical, professional uncertainty is fundamental to any comprehension of the interior, and hence it is central to the condition, i.e. the cultures of education, practice, theory, history and the profession of the subject.