Putnam has grasped the major issues and main trends of contemporary philosophy extensively and deeply. In this book, a large number of philosophical problems affect many philosophical branches, such as philosophy of language, philosophy of logic and philosophy of spirit. Explain it in simple terms, especially the unique views on the essence, rationality and history of truth, aiming at breaking a series of dichotomy thinking modes that have dominated philosophers and ordinary people for a long time and overcoming a series of subjectivity and objectivity, facts and values, dogmatism and relativism.