  Most of Ingarden’s major work focuses on ontology, which he considers a purely a priori enterprise, concerned not with what actually exists, but with what could possibly exist (which concepts are non-contradictory), and with what (according to the contents of the relevant ideas) it would take for objects of various kinds to exist, or entail if they existed. He thus contrasts ontology with metaphysics, which is concerned with answering factual questions about what sorts of things actually exist and what they are like. Ontology, in Ingarden’s hands, thus bears close resemblance to the sorts of conceptual analysis that became common in analytic philosophy in roughly the same period. Ingarden’s work on the ontology of art is ontological in this sense, e.g. he attempts to determine, by analysis of the essential meanings of experiences that could present something as a work of literature, music, or architecture, what sort of an entity such an object would have to be to satisfy those experiences and meanings, and how it would have to relate to consciousness and physical objects.