  To tell whether a plan achieves its goal, you need to see whether the goal holds in the plan’s final state. Doing this requires predictive reasoning, a type of reasoning that was neglected in the tense-logical literature. As in mechanics, prediction involves the inference of later states from earlier ones. But (in the case of simple planning problems at least) the dynamics are determined by actions rather than by differential equations. The investigation of this qualitative form of temporal reasoning, and of related sorts of reasoning (e.g., plan recognition, which seeks to infer goals from observed actions, and narrative explanation, which seeks to fill in implicit information in a temporal narrative) is one of the most impressive chapters in the brief history of common sense logicism.