Christina Kittsteiner

The nowadays relatively unknown Sorites diagram visualizes Sorites syllogisms, i.e., chains of multiple interconnected syllogisms which form large arguments, proofs or chains of evidences. Since these chains of syllogisms are not limited in size or the number of syllogisms they contain, Sorites syllogisms can become very complex and confusing. The Sorites diagram depicts them in a comprehensible way and enables a clear reading that supports the understanding of the matter. Despite its long history and frequent use by various logicians all over the world in the 18th and 19th century, the Sorites diagram fell into oblivion at the beginning of the 20th century and has not yet made its comeback into the field of diagrammatic logic. Because of this, it is very underrepresented in research. This paper aims to shed some light on the forgotten diagram by presenting the Sorites diagram and its many different styles that include lines, trees and circles. Because of its flexibility and comprehensibility, many current fields of science including, among others, diagrammatic logic and argumentation theory, can benefit from the features the Sorites diagram offers.

Arthur Schopenhauer was one of the first logicians of the 19th century to develop a visual representation of the sorites with which it is possible to depict multiple terms in one diagram. With the help of an example from Seneca, he explains how the sorites diagram works and provides two reading interpretations for the diagram. Since Schopenhauer’s sorites diagram in particular or sorites diagrams in general have never been dealt with in research before, this paper will introduce and analyse Schopenhauer’s sorites diagram and its different reading possibilities. Thereby, it will not only be shown how the sorites diagram can help to dissolve the sorites back into individual syllogisms, but also other topics such as the reading directions, the extension and intension of the sorites diagram will be discussed in more detail. It turns out that Schopenhauer’s sorites was just the foundation for further works in his philosophical system.