Since 1985 was published in China, The Theory of Man has caused great influence. From the first printing to the sixth printing of 1997, more than 240,000 copies have been sold, which is undoubtedly a miracle in the sales of academic books. This year, this book was included in the "Century Library", all of which well illustrated the value of this book.

The author Ernst Cassirer (1874- 1945) is a famous German philosopher and philosophy historian. He was trained in Neo-Kantian philosophy in his early years and soon became one of the representatives of Marburg School. He is a professor and president of the University of Hamburg, during which he founded his own "cultural philosophy" system. 1933 Hitler came to power in Germany, and Cahill angrily resigned as the president of Hamburg University and began to live in exile. Later 1945 died and became the president of Columbia University. Cassirer's life works are numerous and rich in content, and his research scope covers almost all fields of contemporary western philosophy. He is recognized by western academic circles as one of the most important philosophers since this century.

Cahill's "cultural philosophy" system has been systematically discussed in his three-volume Philosophy of Symbolic Form. On Man is a book that briefly expounds the basic ideas of symbolic form philosophy in English after he arrived in the United States in his later years, but it also adds many new ideas. Shanghai Translation Publishing House published the Chinese version of 1985, which was translated by Gan Yang.

The book On Man has 12 chapters and is divided into two parts. The first five chapters of the last chapter focus on answering "what is a person?" The first chapter, "The Crisis of Human Self-knowledge", after summarizing various philosophical theories about human problems in the history of western thought for more than two thousand years, puts forward that although science and technology have made unprecedented development in contemporary society, the problem of human self-knowledge has not been really solved, but has fallen into a profound crisis. In the next chapter, Cahill puts forward his own definition of man. In his view, people are not so much "rational animals" as "symbolic animals", that is, animals that can use symbols to create culture. The fundamental difference between humans and animals is that animals can only make conditional responses to "signals", and only humans can turn these "signals" into meaningful "symbols". Although people and animals live in the same physical world, the living world of people is completely different from the natural world of animals. The secret of this difference is that people can invent and use all kinds of "symbols", so they can create their own "ideal world"; Animals can only reflect all kinds of "signals" given to them by the physical world all the time, and cannot get rid of the "real world". The difference between the human world and nature constitutes the basic content of the first part of On Man.

In the last seven chapters of the next chapter, people and culture makes a comprehensive survey of the human world itself and studies how people use various symbols to create culture. In Cahill's view, the study of human beings can only be the study of human culture. The next chapter studies various phenomena of human culture in turn, such as myth, religion, art and science. Trying to prove that all human cultures are the products of people's own creation and use of symbols.

Cassirer studied the "symbolic function", an extremely important human activity ability, in On Man, but he abstractly attributed the "symbolic function" to a transcendental human ability to construct symbols, which reflected the idealistic nature of his philosophy.