Tech Report CS-89-23

A Logic for Emotions: A Basis for Reasoning About Commonsense Psychological Knowledge

Kathryn E. Sanders

March 1989


There is a body of commonsense knowledge about human psychology that we all draw upon in everyday life to interpret our own actions and those of the people around us. In this paper, we define a logic in which this knowledge can be expressed. We focus on a cluster of emotions, including approval, disapproval, guilt, and anger, most of which involve some sort of ethical evaluation of the action that triggers them. As a result, we are able to draw on well-studied concepts from deontic logic, such as obligation, prohibition, and permission. We formalize a portion of commonsense psychology and show how some simple problems can be solved using our logic.

In order to handle concrete problems, since emotions do not occur in a vacuum, it is also necessary to formalize some commonsense knowledge about actions and the probable evaluation of those actions. Specifically, we focus on a cluster of actions having to do with ownership and possession of property --- giving, lending, selling, and stealing. We demonstrate that our logic is sufficiently expressive to handle a variety of information about human actions and responses in a way that is substantially more formal than previous work in this area.

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