ABSTRACT
The concept of “constraint” describes the operation of data models and the ways in which we actually experience their power to govern and shape. Constraint is a process of measurement and enforcement whose goal is to enable interaction between systems: between data and tools, between plugs and sockets, between different senders and receivers of information. The principles of set theory and classification offer a particular kind of perspective on constraint: its function of enforcing a division of the world into “the things that belong” and “the things that do not belong.” From the viewpoint of someone using the constraints to create or interact with data the experience may be quite different. The formal constraints themselves situated in a larger context: a set of standards and agreements that constitute a kind of social contract concerning the nature of information and the modes of its expression.
