 Scholz analyzed classical metaphysical doctrines with his logical tool of a predicate calculus with identity. His considerations are based on a special variation of a Platonic ontology combined with Leibniz’s notion of possible worlds, the Frege-Russell mathematical logic, Hilbert’s axiomatic method, and Tarski’s semantics. This approach found its final expression in the influential textbook Grundzüge der mathematischen Logik which was elaborated, co-authored, and published by Gisbert Hasenjaeger after Scholz’s death (Scholz and Hasenjaeger 1961). Hasenjaeger later called its philosophical background “discrete ontology”, a realistic position: “The world of concrete (or also abstract) things consists just of things which have some features and do not have others; between them some relations are given, others not” (Hasenjaeger 1962, pp. 30–31).