Open World Assumption Concept

In formal logic, the open world assumption (OWA) is the assumption that the truth-value of a statement is independent of whether or not it is known by any single observer or agent to be true. It is the opposite of the closed world assumption, which holds that any statement that is not known to be true is false. The open world assumption is used in knowledge representation to codify the informal notion that in general no single agent or observer has complete knowledge, and therefore cannot make the closed world assumption.

"Open" in this case is unrelated to the sense in open source software or open methodologies (as is MIKE2.0). "Open" in OWA represents a way to look at the world versus "open" as in free.

Systems and methodologies that embody open world v closed world approaches have many differences with regard to completeness, incrementalism, or costs and risks.