  This paper introduces conceptual relations that synthesize utilitarian and
logical concepts, extending the logics of preference of Rescher. We define
first, in the context of a possible worlds model, constraint-dependent measures
that quantify the relative quality of alternative solutions of reasoning
problems or the relative desirability of various policies in control, decision,
and planning problems. We show that these measures may be interpreted as truth
values in a multi valued logic and propose mechanisms for the representation of
complex constraints as combinations of simpler restrictions. These extended
logical operations permit also the combination and aggregation of goal-specific
quality measures into global measures of utility. We identify also relations
that represent differential preferences between alternative solutions and
relate them to the previously defined desirability measures. Extending
conventional modal logic formulations, we introduce structures for the
representation of ignorance about the utility of alternative solutions.
Finally, we examine relations between these concepts and similarity based
semantic models of fuzzy logic.
