Wolak, Zbigniew (Instytut Teologiczny w Tarnowie, 1999)
This paper presents a method of the graphic proofs in propositional calculus. We can use diagrams, similar to Venn’s diagrams to draw premisses and inferences. Then we can check their validity. The diagrams enable us to see whether premisses are sufficient or two strong and what other inferences could be derived. The graphic method could be used as an educational aid in teaching logic. Sometimes it is simpler than other methods, sometimes it is more difficult, but always it is creative. One more advantage of the graphic method is the possibility of using computer programs in performing logical proofs.
