When Do We Say That a Diagram is a Logic Diagram? A Comparative Study
Although the representative advantages of diagrams have been widely recognized, their inferential virtues have not always received the same attention. There is a tradition that holds that reasoning based on linguistic proofs is essential in logic and mathematics, but that reasoning based on diagrams is not; however, thanks to some research projects on diagrammatic reasoning, today we have models that help us understand the concepts of logic diagram and diagrammatic inference with more precision. By following the tenets of these models, in this contribution we perform a comparative study of ten diagrammatic systems in logical and representative terms with the purpose of offering an answer to the question of what makes a diagram a logic diagram. Our preliminary answer is that a logic diagram is a diagram within a diagrammatic system that is correct and complete with respect to a class of valid inferences given a deductive base. This definition seems to be adequate because it allows us to include those systems of diagrams that, due to their properties, we typically consider as bona fide logic diagrams, but it excludes diagrams that are not only incorrect or incomplete, but those that are not even inferential.