If Plato is wise, then at least three elements are involved - Plato, wisdom and Plato's wisdom. These are exemplary representatives of three ontological categories (substance, universal quality, particular quality) which are fundamental to our orientation in the world. Drawing on aspects of language philosophy and logic, Schnieder develops a conception of these categories and their interconnections. The book is also suitable as a general critical introduction for readers without special grounding in ontology.