Chronological Ignorance: Time, Nonmonotonicity, Necessity and Causal Theories

Concerned with the problem of reasoning efficiently about change within a formal system, we identify the initiation problem. The solution to it which we offer, called the logic of chronological ignorance, combines temporal logic, nonmonotonic logic, and the modal logic of necessity. We identify a class of theories, called causal theories, which have elegant model-theoretic and complexity properties in the new logic.