Abstract
John Heil's new book (Heil 2003) is remarkable in many ways. In a concise, lucid and accessible manner, it develops a complete system of ontology with many strikingly original features and then applies that ontology to fundamental issues in the philosophy of mind, with illuminating results. Although Heil acknowledges his intellectual debts to C. B. Martin (p. viii), he is unduly modest about his own contribution to the development and application of this novel metaphysical system. A full examination of the position that Heil defends would require a book in itself, so I shall limit myself to discussing some of its central themes and to explaining a few doubts that I have concerning some aspects of it.