In sociology, field theory examines how individuals construct social fields, and how they are affected by such fields. Social fields are environments in which competition between individuals and between groups takes place, such as markets, academic disciplines, musical genres, etc.
Unstable fields are defined by rapid change and frequently by destructive forms of competition, such as pure competition over prices that drives profit margins to untenably low levels. Fields thus need to be stabilized with rules which make sure that competition takes non-destructive forms. Stable fields rarely emerge on their own, but must be constructed by skilled entrepreneurs. The government frequently plays a role in this process as well.
Fields feature different positions which social actor can occupy. The dominant players in the field are called the incumbents. They are generally invested in maintaining the field in its current form, as changes to the rules of competition risk destabilizing their dominant position. Fields may also feature insurgents who instead aim to alter the field so they can successfully compete with the incumbents. Dramatic change in previously stable fields can come from either successful incumbents or intrusion from other fields, or from government-imposed rule change.
In general, different field positions create different incentives. Field position is experienced by individuals in the form of motivation.