Logical diagrams in Serbian medieval manuscripts

Visual rendering of logical relations represent an interesting, although (so far) completely neglected part of Serbian medieval philosophy. The attempts to visualize conceptual connections or differences must not be viewed as sheer illustrations, let alone purely decorative ornaments, but as vivid traces of a deeper intellectual striving to gain more insight into the subject by means of certain pictorial shapes or accompanying scholia. Roughly speaking, Serbian diagrams occur in three major forms: 1) Divisions (dichotomous, trichotomous, etc) representing conceptual classifications in the manner of the Porphyrian tree or its parts, 2) Reversed arches with one, two or more salient points, viz., upright or upside down triangles denoting syllogisms according to the three recognized figures and their respective aberrations (paralogisms); 3) Crossed diagonals inscribed or not into a square indicating mutual differences of the so called voces (terms) or propositions. While their extremely abstract character allows shifting applications, which in turn always require a context bound interpretation, they were initially designed to serve three main goals: First, provide a backdrop for perfect definitions (genus + specific difference), second, demonstrate the flow of implication or lack of it in particular conclusions, and finally, illustrate multiple simultaneous relations which cannot be properly depicted in a linear dichotomy scheme. All these patterns, through the medium of Byzantine models they emulate or simply translate, could be traced down to the tradition of ancient commentators and ultimately Aristotle, who is widely credited with the introduction of visual representation in logic. While only some of them are still echoed in contemporary logic, they all shed an important light on the ways how ancient diagrams were used, transformed or forgotten, before modern patterns of visual representation were developed by the end of the 18th century.