Causal Propagation Semantics - A Study

A unifying semantic framework for different reasoning approaches provides an ideal tool to compare these competing alternatives. A historic example is Kripke’s possible world semantics that provided a unifying framework for different systems of modal logic. More recently, Shoham’s work on preferential semantics similarly provided a much needed framework to uniformly represent and compare a variety of nonmonotonic logics (including some logics of action). The present work develops a novel type of semantics for a particular causal approach to reasoning about action. The basic idea is to abandon the standard state-space of possible worlds and consider instead a larger set of possibilities — a hyper-space — tracing the effects of actions (including indirect effects) with the states in the hyper-space. Intuitively, the purpose of these hyper-states is to supply extra context to record the process of causality.