Possible Models Diagrams: a new approach to teaching propositional logic.
Matthew C. Clarke · ResearchSpace (University of KwaZulu-Natal) · 1994
Possible Models Diagrams (PMDs) are simple graphs which may be used to represent propositional expressions.Technically, these graphs are hypercubes in which the vertices are partitioned into two sets: one representing the possible models in which the propositional expression turns out to be true, and the other representing the possible models in which the propositional expression turns out to be false.PMDs can be used to define boolean operators, to analyse whether a propositional expression is tautological, contingent or inconsistent, and to determine the validity of propositional sequents.This dissertation describes both theoretical and pedagogical aspects of PMDs, and places this new approach within the context of a course on logic for first year computer science students.In this course, various forms of logical representation are taught and the ability to translate between those representations is emphasised.An extensive comparison is made between PMDs and other methods of teaching propositional logic.In particular, qualitative and quantitative evidence is given to show that students perform better when using PMDs than they do when using truth tables.The advantage of PMDs for the purpose of teaching is that they are iconic: that is, they are symbolic pictures which combine the expressive power of symbolism with the memorability of visual images.