 Stumpf’s contribution to metaphysics has been the subject of recent studies, (K. Schuhmann, 1999; D. Jacquette 2000–2001; R. Rollinger, 2008b; R. Martinelli, 2011, 2015) and his lectures on metaphysics delivered in Halle in the late 1880s has been recently published. (C. Stumpf, 2015) He distinguished following Brentano four main branches of metaphysics: transcendental philosophy, which focuses on the justification of our knowledge of the external world, ontology whose domain includes, in addition to the categories, the topic of psychophysical relations and that of causality among other things; thirdly, theology which is concerned with the evidence of the existence of a foundation of the world, and finally, cosmology which deals namely with issues related to the actual infinite.