In this paper, we analyze and discuss Schopenhauer's nterm diagrams for eristic dialectics from a graph-theoretical perspective. Unlike logic, eristic dialectics does not examine the validity of an isolated argument, but the progression and persuasiveness of an argument in the context of a dialogue or even controversy. To represent these dialogue situations, Schopenhauer created large maps with concepts and Euler-type diagrams, which from today's perspective are a specific form of graphs. We first present the original method with Euler-type diagrams, then give the most important graph-theoretical definitions, then discuss Schopenhauer's diagrams graph-theoretically and finally give an example of how the graphs or diagrams can be used to analyze dialogues.