A major debate on what constitutes truth
A major debate on what constitutes truth, initiated forty years ago under Deng Xiaoping and other revolutionary leaders of his generation, unfolded among Party members and the general public. It was about whether we should seek truth from facts or abide by the decisions Chairman Mao had made or the instructions he had given.
In the mid and late 1970s, blind adherence to the words of Mao effectively blocked China's march forward. To break these shackles, Deng championed a clear departure from this dogmatic mentality, which – as he pointed out on many occasions – ran counter to Marxism. He also highlighted the importance of a more comprehensive and accurate understanding of Mao Zedong Thought. Theoretical Trends, an in-house journal of the Party School of the Central Committee, published an article on May 10, 1978 entitled "Only Practice Leads to Truth." The article categorically refuted any dogmatic formula for following Mao's instructions. It unequivocally pointed out that according to basic Marxist principles, the only test for truth was practice, and that a theory must be tested continuously through practice in order to prove its validity. The article was published in the Guangming Daily the next day, and was released nationwide through Xinhua News Agency. It sparked heated debate within the Party and among the general public on what constitutes truth.
With strong and timely support from Deng and other revolutionary leaders, the debate enabled the public to think about the important question of how to chart a course for the country's future development, and allowed China to break free from the dogmatic formula for following Mao's instructions. It spurred a nationwide ideological emancipation campaign that promoted a true understanding of Marxist teachings, laid the ground for the third plenary session of the 11th CPC Central Committee, and led the Party to reaffirm Marxist principles as its guiding ideological, political and organizational principles.
The dogma advocating blind adherence to the words of Mao was roundly repudiated at the third plenary session of the 11th CPC Central Committee. Conclusions were reached, acknowledging and applauding the outcome of the debate on what constitutes truth, and reaffirming the relevance of Marxism. What the Party accomplished at this gathering marked the dawn of a new era of reform and opening up.
真理标准问题大讨论
真理标准问题的讨论，是40年前在邓小平等老一辈无产阶级革命家的领导和支持下，在全党全国范围内开展的一场大讨论，主要表现为实事求是和“两个凡是”的争论。
20世纪70年代中后期，中国面临着“两个凡是”（即：凡是毛主席做出的决策，我们都坚决维护；凡是毛主席的指示，我们都始终不渝地遵循）错误方针的严重阻碍。针对这种状况，邓小平多次旗帜鲜明地提出，“两个凡是”不符合马克思主义，我们要完整准确地理解毛泽东思想。1978年5月10日，中央党校内部刊物《理论动态》发表了《实践是检验真理的唯一标准》一文，鲜明指出，社会实践是检验真理的唯一标准，任何理论都要不断接受实践的检验等马克思主义的基本原理。这就从根本理论上否定了“两个凡是”。5月11日，这篇文章在《光明日报》公开发表，新华社向全国转发，在党内外和广大干部群众中引起强烈反响，全国上下就此开始“真理标准问题大讨论”。
邓小平等老一辈革命家对这场讨论给予及时而有力的支持，使大讨论的过程成为引导人民思考国家向何处去这一重大课题的过程。这场大讨论，冲破了“两个凡是”的严重束缚，推动了全国性的马克思主义思想解放运动，为党的十一届三中全会的召开做了重要的思想准备，为党重新确立马克思主义的思想路线、政治路线和组织路线奠定了思想基础。
党的十一届三中全会坚决批判了“两个凡是”的错误方针，总结并高度评价了真理标准问题大讨论，重新确立了马克思主义的正确路线，开启了改革开放历史新时期。