Written by an eminent and original thinker in the philosophy of science, this book takes a fresh, unorthodox look at the key philosophical concepts and assumptions of the social sciences. Mario Bunge contends that social scientists (anthropologists, sociologists, political scientists, economists, and historians) ought not to leave philosophy to philosophers who have little expertise in or knowledge of the social sciences. Bunge urges social scientists to engage in serious philosophizing and philosophers to participate in social research. The two fields are interrelated, he says, and important advances in each can supply tools for solving problems in the other. Bunge analyzes such concepts as fact, cause, and value that the fields of philosophy and social science share. He discusses assumptions and misassumptions involved in such current approaches as idealism, materialism, and subjectivism, and finds that none of the best-known philosophies helps to advance or even understand social science. In a highly critical appraisal of rational choice theories, Bunge insists that these models provide no solid substantive theory of society, nor do they help guide rational action. He offers ten criteria by which to evaluate philosophies of social science and proposes novel solutions to social science's methodological and philosophical problems. He argues forcefully that a particular union of rationalism, realism, and systemism is the logical and viable philosophical stance for social science practitioners.