 Metaphysics is importantly present in Content and Object, and particularly important are the mereological considerations Twardowski offers. According to Ingarden, Content and Object offered “the first consistently constructed theory of objects manifesting a certain theoretical unity since the times of scholasticism and of the ‘ontology’ of Christian Wolff” (1948, 258). One cannot literally agree with Ingarden considering the Leibnizian metaphysics in Bolzano's Athanasia (1827)—hidden in the two-thousand pages of the Wissenschaftslehre—and Brentano's work in mereology. Nevertheless, if the impact of Content and Object is compared with that of Bolzano's or Brentano's metaphysics, things are different. Content and Object was a fundamental contribution to the renaissance of Aristotelian metaphysics—metaphysics in the sense of a general theory of objects—which led to both Meinong's theory of objects and to Husserl's formal ontology of parts and wholes in the Third Logical Investigation. The story continues, later, with Leśniewski's mereology and Ingarden's ontology. The heritage of Content and Object also includes the fact that Twardowski's pupils had a relation to metaphysics which was vastly different from the approach that was typical, for instance, of the Vienna circle (see Łukasiewicz 1936). In Poland, metaphysics was not rejected as nonsense, but accepted as a respectable area of investigation to be explored using rigorous methods, including axiomatics (see Smith 1988, 315–6; on Twardowski and metaphysics, see Kleszcz 2016)