Interfaces are both surfaces and thresholds. On the one hand, an interface is a kind of surface screen, whether literal or figurative, that contains meanings and operations. On the other hand, an interface is a window or doorway that facilitates passage.

As window or door, the interface serves a boundary function, for example, between the human body and the external world of apparatuses and devices. More generally, an interface is any distinction made between something and something else: HTML is the interface between legible text and markup tags; the freezing point is the interface between water and ice. Interfaces are physical or symbolic markers of difference. They constitute the articial distinction between two media and allow media to be remediated into other forms. Given their role as differentiators, interfaces exist in relations that are systemic, layered, or nested. To facilitate such systemic architecture, interfaces require intricate codication and regulation. Interfaces are zones of exchange and as thresholds they are productive and generative. Yet as regulators, they also restrict or delay passage. Hence interfaces display a dialectical tension between the immediate and the arcane, the clear and the complicated, or the evident and the inscrutable.

Yet interfaces are not simply thresholds, they are also surfaces or screens. An interface is what Vilém Flusser calls a “significant surface” (Towards a Philosophy of Photography, 1984, p. 6). Thus in addition to being a zone of decision that facilitates exchange and passage, an interface is also an “‘undefined zone’ between the inside and the outside” (Genette, Paratexts, 1997, p. 2). Not just doorways, interfaces also have their own internal reality; they support an autonomous aesthetic space. Edge and center combine within the interface, binding together the frame and the work. Interfaces thus link both inside and outside.

Original article by Alexander Galloway