 Inquiry on the origins of concepts, as we said, is a task specific to psychology. In contrast, the theory of knowledge is limited to the research and justification of “the most general and immediately evident truths” (Stumpf, 1891, p. 501), such as laws and axioms necessary for knowledge. Yet, these axioms are nothing but propositions that we assume to be true and necessary, and they have their origin in the content of a specific class of psychical functions, namely judgments. Since the contents of judgments are formations or products (Gebilde) which, as we said, belong to eidology, the field of research of the theory of knowledge is therefore linked to that of this neutral science which also includes states of affairs. One must therefore avoid confusing the question pertaining to the nature of axioms with that of the psychological origins of concepts, but one can no more entirely separate the theory of knowledge from descriptive psychology since axioms are originally the contents of a specific class of psychical functions, i.e. the contents of judgments or of propositional attitudes whose justification is the task of the theory of knowledge. (Stumpf, 1891, p. 495–496; 1939–1940, p 124)