first, the theory of centralization. The right of communication is firmly in the hands of the ruling class, who are mostly feudal nobles and princes and ministers. Private newspapers are subject to strict scrutiny, and the ruling class generally suppresses people's free speech by issuing licenses and tax subsidies. Dangerous remarks against the ruling class. Those who are light will ban newspapers and close them, while those who are heavy will be punished and killed.
second, the theory of liberalism. After the bourgeoisie gained the leadership, capitalism entered a period of free competition, adhering to the principle of their struggle against feudal rule and creating a liberal communication system. The basic idea of liberalism is that everyone has the right to express his opinions, and truth should be tested in the market of free opinions, even lies and slanders should be allowed to be expressed, because truth will never be submerged. The most classic liberalism theory is Jefferson's famous saying: Although I object to your opinion, I will defend to the death your right to express your opinion. But in fact, it is impossible for everyone to express their opinions. First of all, there are economic restrictions, and the cost of running a newspaper is getting higher and higher. Secondly, there are political restrictions. After the proletarian awakening, the speech is suppressed by the bourgeoisie.
third, the theory of social responsibility. After capitalism entered the period of monopoly competition, newspapers' unlimited pursuit of the greatest interests and disregard for social responsibilities led to the proliferation of political newspapers and "scandal sheet", which made it difficult for people to distinguish the truth from the truth in the massive information, violating the principle of objective truth of news, and the capitalist society before World War II was once turbulent. Accompanied by state capitalism and monopoly capitalism comes the theory of social responsibility in the communication system, which emphasizes that newspapers should guide public opinion, and unrestricted freedom of speech can only destroy freedom itself, and advocates that newspapers' social responsibility is higher than newspapers' freedom of the press, which has played a certain role in curbing "yellow news" and "political propaganda".
fourth, the theory of socialism. This is the communication system adopted by socialist countries since the founding of the Soviet Union, which clearly points out the mouthpiece role of newspapers and other mass media. Lenin believes that newspapers are propagandists, agitators and organizers of the revolution, which is different from that of the bourgeoisie. The proletariat is not shy about its own communication system, and thinks that mass media serve the proletariat and proletarian revolution. Referring to the existing system in China, the mass media are all owned by the state, adopting a unified propaganda policy and operating independently, and its propaganda means and contents must adhere to the direction of socialist political civilization and spiritual civilization.
The four theories of newspapers and periodicals are also applied to other mass media. Nowadays, western countries implement the communication system of social responsibility theory at home, and call for the implementation of liberal communication system abroad, in order to seek domestic stability and maximize global interests. China still implements the socialist communication system, but has begun the market-oriented reform of mass media, which will enable the media to better integrate into the global market economy system and seek greater development in the future.