Abstract

In this paper, I aim to identify Peirce’s great contribution to logical diagrams and its limit.Peirce is the first person who believed that the same logical status can be given to diagrams as to symbolic systems.Even though this belief led him to invent his own graphical system, Existential Graphs, the success or failure of this system does not determine the value of Peirce’s general insights about logical diagrams.In order to make this point clear, I will show that Peirce’s revolutionary ideas about diagrams not only overcame some important defects of Venn diagrams but opened a new horizon for logical diagrams.Finally, I will point out where Peirce’s new horizon for logical diagrams stopped and will claim that this limit is mainly responsible for the discrepancy between Peirce’s and others’ estimates of his contribution to logical diagrams.