"Meinong's Jungle" is the term used to make fun of Alexius Meinong's ontology. He believed that when we make references to objects in language, the meaning of the words is grounded by the existence the object being referred to. So if we say "Pegasuses have wings", in order for that sentence to be true, Pegasuses must in some sense exist, in order to even have properties and be referred to by language. Russell and others thought this was absurd, and coined the term "Meinong's Jungle" as the place where all these non-existant things where said to exist.

The rest of the comic is references various other reference problems and language thought experiments that puzzled philosophers at that time, such as the "morning star / evening star" problem, or "cicero is tully", the "Twin Earth thought experiment", the "possible bald man", Avicenna's distinctions between different types of Existence and Essence, and the discussion of tautolgies in sentences like "unmarried bachelor" or logical impossibilites of "married bachelor".