The essays in this volume were written by philosophers who are convinced that Wittgenstein's investigations in philosophical psychology are of direct relevance to current experimental psychology. Rather than reflecting on the nature of psychological theory at a high level of abstraction, they have examined leading theories and controversies in the experimental study of vision and of language in order to reveal the conceptual problems that they raise and the philosophical theories which have exerted an influence upon them. Under the section headings of "Language and Behaviour" and "Perception and Representation", the essays examine the work of Chomsky, Gregory, Marr, Weiskrantz and others, and discuss problems ranging from artificial intelligence to animal communications, from blindsight to machine visions. The collection aims to demonstrate that philosophical investigations can contribute to psychological science by extirpating conceptual confusions which have been woven into the fabric of empirical research. This book should be of interest to advanced students and teachers of the philosophy of mind.