Observable human commonsense reasoning can be modeled with graded propositional logic. Our approach is distinctive in that all mathematical models are directly linked to specific, observable, and explainable mental activities. Decision-makers evaluate alternatives through perceived gradations of truth, importance, suitability, simultaneity, and substitutability. Each graded variable has a semantic identity, reflecting its role and meaning tied to the goals and interests of a specific decision-maker.Graded logic was introduced 50 years...
