This book explores in detail the relation between ontology and ethics in the early work of Ludwig Wittgenstein, notably the Tractatus Logico-Philosophicus and, to a lesser extent, the Notebooks 1914-1916. Self-contained and requiring no prior knowledge of Wittgenstein's thought, it is the first book-length argument that his views on ethics decisively shaped his ontological and semantic thought. The book's main thesis is twofold. It argues that the ontological theory of the Tractatus is fundamentally dependent on its logical and linguistic doctrines: the tractarian world...