 Ingvar Johansson (1989) and Roderick Chisholm (1996) both take a neo-Aristotelian realist approach to categories, attempting to lay out a complete system of the categories, where this is understood as providing a list of categories of real entities in the world. Ingvar Johansson explicitly insists that his interest is in the world: “This book is a book about the world. I am concerned with ontology, not merely with language” (1989, 1), and attempts to offer “a realist theory of categories regarded as real aspects of being” (1989, 2). His list (1989, 20) includes nine main categories (some of which subdivide further):