 There is a remarkable continuity in the work of Stumpf regarding his positions from his habilitation thesis up to his posthumous work, not only on the foundation of mathematics but also on the theory of knowledge. One of the main theses he advocates in Erkenntnislehre is based on the distinction between the origins of concepts and the origins of knowledge. (Stumpf, 1939–1940, § 1) Stumpf revisits the theme of mathematical axioms (Stumpf, 1939–1940, §§ 12–13) in the context of a critical discussion of Husserl’s doctrine of formal and regional ontologies. Stumpf’s conception of the concept of number in Erkenntnislehre is the same as the one he advocated in his habilitation thesis and in his Halle lectures, and Stumpf’s position is very similar to that of Brentano and his students. (W. Ewen, 2008, p 162 f.; C. Ierna, 2015) In this regard, Stumpf’s influence on his student Husserl’s habilitation thesis regarding the origins of the concept of number, including Husserl’s conception of symbolic presentations, is to be considered. (D. Münch, 2002, pp. 31–37)