A diagrammatic approach to Peirce’s classifications of signs

Starting from an analysis of two diagrams for 10 classes of signs designed by Peirce in 1903 and 1908 (CP 2.264 and 8.376), this paper sets forth the basis for a diagrammatic understanding of all kinds of classifications based on his triadic model of a sign. Our main argument is that it is possible to observe a common pattern in the arrangement of Peirce’s diagrams of 3-trichotomic classes, and that this pattern should be extended for the design of diagrams for any n-trichotomic classification of signs. Once this is done, it is possible to diagrammatically compare the conflicting claims done by Peircean scholars regarding the divisions of signs into 28, and specially into 66 classes. We believe that the most important aspect of this research is the proposal of a consolidated tool for the analysis of any kind of sign structure within the context of Peirce’s classifications of signs.