47 years ago today, on May 11th, 1978 (April 5th, 1978 in the lunar calendar), Guangming Daily published "Practice is the only criterion for testing truth". On May 11th, 1978, Guangming Daily published a special commentator's article entitled "Practice is the only criterion for testing truth". On the same day, Xinhua News Agency forwarded this article. On the 12th, People's Daily and People's Liberation Army Daily reprinted it at the same time. This paper discusses Marxism-Leninism's viewpoint of practice first, and correctly points out that any theory should be tested by practice. Marxist theory is not a bunch of stiff dogmas. It needs to constantly add new contents in practice. Of course, there is still the erroneous tendency that "what is uploaded in the Bible is right". This is the spiritual shackle imposed on people by the Gang of Four, and it must be resolutely broken. This article sparks discussion on the issue of practice as the only criterion for testing truth. The vast majority of people inside and outside the party support and support the views of the article. Although Hua Guofeng instructed some leaders of the central propaganda department to "not express their position" or "not get involved" in the discussion of the standard of truth; On some occasions, Wang Dongxing accused this article of "actually pointing the finger at the chairman's thoughts" and asked, "Which central opinion is this?" To suppress it. However, this discussion was actively supported by most comrades of the CPC Central Committee, such as Deng Xiaoping, Ye Jianying, Li Xiannian, Chen Yun and Hu Yaobang, and the discussion was gradually carried out throughout the country. From June to November, the main responsible comrades of various departments of the Central Party, government and army, and most provinces, municipalities, autonomous regions and major military regions across the country published articles or speeches, unanimously believing that adhering to the Marxist principle that practice is the only criterion for testing truth is of great practical significance. This discussion prepared ideological conditions for the convening of the Third Plenary Session of the Eleventh Central Committee of the Party. In a sense, this is the loudest and most critical slogan in 20 years. Since the Cultural Revolution, a "highest instruction" worth 10,000 sentences has become the only criterion for testing truth. No one has ever dared to ask: What should be used to test the "highest instruction"? The proposal of this slogan is not simply to challenge Mao Zedong's unquestionable authority, but to pave the way for new exploration. With the authoritative establishment of the concept that "practice is the only criterion for testing truth", countless unjust, false and wrong cases have been corrected, and batches of farmers have been allocated land. Since the reform started in rural areas, people no longer regard getting rich as a sin, and more and more new things have overwhelmed Chinese people's horizons. Of course, more importantly, Chinese people have embarked on a pragmatic road since then, which is really a slogan and has changed Chinese people's lives. Hu Fuming, one of the original authors of the article, Yang Xiguang, editor-in-chief of Guangming Daily at that time