Story themes are generalized advice that a story contains, and theme recognition provides a way for a system to show that it has understood the story. T H U N D E R is a story understanding system that implements a model of theme construction from belief conflicts and resolutions. A belief conflict is conflicting evaluative beliefs regarding a story character's plan. W h e n execution of the plan results in a realized success or failure for the character, a resolution to the conflict is recognized from the additional reasons that the realization provides for the evaluative beliefs in conflict. The theme of the story is generated by reasoning about how the resolution shows the beliefs in conflict to be correct or incorrect, and produces a statement of generalized advice about reasons for evaluation. T w o types of advice are generated by T H U N D E R : (1) reason advice about the reasons for evaluation that the story shows to be correct, and (2) avoidance advice about how failures that occur as the result of erroneous evaluations could be avoided. The algorithms for constructing both type of advice and examples of T H U N D E R constructing themes are presented.

During story understanding readers make value judgments—^judgments of the "goodness" or 'badness' of characters' actions. This paper presents the representational structures and processes used to make value judgments by the computer program THUNDER. THUNDER creates evaluative beliefs about characters' plans based on a set of universal pragmatic and ethical judgment rules. To account for subjective differences in evaluative belief, THUNDER has a specific ideology to represent the idiosyncratic aspects of evaluation. There are two components in the representation of ideology: (1) a set of important, long term goals called values, and (2) a collection of planning strategies for each value. This representation for ideology allows THUNDER to reason about what is 'good', and what it believes to be 'good ways to get what is good.' The representation and rules for value judgments are used to (1) make inferences about character belief and ideology, (2) represent expectation knowledge based on personality traits, and (3) reason about the obligations that characters acquire.