Closed World Assumptions
Ian E. Pratt-Hartmann · 1994
The lesson of chapter 3 is that theorem-proving in the predicate calculus constitutes a poor mechanism for reasoning about a complex, dynamic environment such as the one we inhabit. In particular, we drew attention to the problem of representing negative information — information about the non-existence of objects or events or processes or influences. Negative information, we argued, must sometimes be encoded by the mere absence of positive information to the contrary: propositions which are not given, or which are not deducible from those which are given, should be assumed to be false. This type of assumption is sometimes referred to as a closed world assumption , and the logical properties of closed world assumptions occupy centre stage in one important strand in AI research. They also form the topic of this chapter.