 Stumpf did not publish any specific work on the topic of logic and wrote only a few pieces on language. These are however two topics in which Stumpf was very much interested. The topic of language was central in his 1876 paper on Anton Marty’s dissertation entitled Über den Ursprung der Sprache (A. Marty, 1875; L. Cesalli, 2015). Also worth mentioning is an essay on the psychology of music in England (1885) and his book Die Anfänge der Musik (1911) in which he discussed, in relation to Spencer and Darwin, the thesis of the linguistic origin of music. Finally he made a significant contribution to the field of phonology and conducted an extensive research on the nature of vowels and linguistic sounds, and this led to the publication of his book Die Sprachlaute (1926) in which he experimentally confirms Helmholtz’s principles on the theory of vowels. As to the domain of logic, there are many syllabi and extensive lecture notes, including those written by Husserl during his studies in Halle, which again show a direct influence from Brentano (K. Schuhmann, 1996, 1997; R. Rollinger, 2015). We know that logic is closely related to Stumpf’s theory of relations and eidology, which are central in both his philosophical and empirical works. More precisely, his contribution to logic in these two research areas concerns in fact the specific content of judgment (belief) or what he also calls states of affairs, and that part of the theory of relations pertaining to part-whole relations. The first leads to a theory of the states of affairs while the second was useful in developing a formal ontology, one that was central in the logic of his student Husserl. Finally, mention should be made of Stumpf’s publications on the relationship between logic and the theory of probabilities, and his research pertaining to the elaboration of a theory of induction. He claimed that the application of probability concepts does not involve any presuppositions about the external world and the law of causality, for the calculus of probability is purely a priori and is solely derived from the concept of probability itself.