How does the mind and language shape our social world? How do you build a theory of speech out of a theory of the mind? In this book, John Searle examines these and related questions in contemporary philosophy. He takes the reader through the conceptual problems associated with metaphysics, the biology of the mind, the paradox of intentionality, the structure of consciousness and the organization of the social universe, to present a comprehensive account of what philosophy can and cannot do. He stresses the existence of a real material world and condemns the belief that the reality of the universe depends on our perception of it.