The paper will focus on a theoretical definition of text as interference and of interference as text. The study is based on a reading of an essay by Jacques Derrida, Freud and the Scene of Writing, in which the French philosopher reads two essays by Sigmund Freud, Project for a Scientific Psychology (1985) and A Note Upon the “Mystic Writing-Pad” (1925). Freud analyses the functioning of memory: a Wunderblock as a metaphor for the mind. These texts allow Derrida to describe the movement of difference in terms that define also the movement of the text. The text becomes the object of study from which one should think the interference. Interference is also a way of describing the action of the theory. Praxis is a set of interferences between theoretical points. Deleuze says that a theory should always be deterritorialized. The paper shows that deterritorialization is a form of interference. Writing is interference; every interference is a form of writing.