T. van der Weide

Practical reasoning using values: giving meaning to values

Each person holds numerous values that represent what is believed to be important. As a result, our values influence our behavior and influence practical reasoning. Various argumentation approaches use values to justify actions, but assume knowledge about whether state transitions promote or demote values. However, this knowledge is typically disputable, since people give different meanings to the same value. This paper proposes an argumentation mechanism to argue about the meaning of an value and thus about whether state transitions promote or demote values. After giving an overview of how values are defined in social psychology, this paper defines values as preference orders and introduces several argument schemes to reason about preferences. These schemes are used to give meaning to values and to determine whether values are promoted or demoted. Furthermore, value systems are used for practical reasoning and allow resolving conflicts when pursuing your values. An example is given of how the new argument schemes can be used to do practical reasoning using values.

Arguing about preferences and decisions

Complex decisions involve many aspects that need to be considered, which complicates determining what decision has the most preferred outcome. Artificial agents may be required to justify and discuss their decisions to others. Designers must communicate their wishes to artificial agents. Research in argumentation theory has examined how agents can argue about what decision is best using goals and values. Decisions can be justified with the goals they achieve, and goals can be justified by the values they promote. Agents may agree on having a value, but disagree about what constitutes that value. In existing work, however, it is not possible to discuss what constitutes a specific value, whether a goal promotes a value, why an agent has a value and why an agent has specific priorities over goals. This paper introduces several argument schemes, formalised in an argumentation system, to overcome these problems. The techniques presented in this paper are inspired by multi attribute decision theory. Categories and Subject Descriptors I.2.4 [Artificial Intelligence]: Knowledge Representation Formalisms and Methods. General Terms: Design.