The purpose of a system is what it does, not what its designers say it is meant to do.
Beer's dictum. Its value is as a refusal to accept stated purpose: a system that reliably produces an outcome has that outcome as its purpose, whatever the mission statement says.
In practice
- A complaints procedure that resolves four cases a year in a service with nine thousand users is doing what it does, and its stated purpose is not it.
- A grant process that funds the same six organisations every year has funding those six as its purpose, and the criteria are downstream of that.