This book offers a critical reconstruction of the fundamental ideas and methods in artificial intelligence (AI) research. By paying close attention to the metaphors of AI and their consequences for the field's patterns of success and failure, it argues for a reorientation of the field away from thought and toward activity. By considering computational ideas in a large, philosophical framework, the author eases critical dialogue between technology and the social sciences. AI can benefit from an understanding of the field in relation to human nature, and in return, it offers a powerful mode of investigation into the practicalities of physical realization. Researchers in AI and cognitive science will welcome this timely discussion.