Soft Computing Evaluation Logic

2.5The Percept of Importance and the Use of Weights

The purpose of computing is insight, not numbers.

Richard Hamming

The percept of importance is the fundamental component in evaluation reasoning and in intuitive aggregation of degrees of truth. This is a semantic component—it is based on understanding the definition, origin, and the role of each input degree of truth, as well as its impact on attaining stakeholder’s goals. Therefore, modeling importance is indispensable for development of evaluation criteria.

The presence of the percept of importance in many areas of human reasoning shows that this fundamental percept should regularly be present in mathematical logic. Unfortunately, that is not the case. From the time of Aristotle to the time of Augustus De Morgan and George Boole, all degrees of truth were considered equally important. It is difficult to explain why for many centuries logic was studied primarily as a theoretical mathematical discipline, and not as a discipline of practical modeling of human mental activity. Unsurprisingly, modeling the percept of importance is a fundamental topic in graded logic, and we study it in this chapter.

Human evaluation reasoning evidently combines formal logic and semantic components. If the inputs of an aggregator have any meaningful role and interpretation, they will immediately and automatically have perceptible degrees of importance. We can safely claim that degrees of importance are indispensable whenever arguments are ...