中晚唐时期是唐代社会的转型阶段，在这一时期，政治、经济、思想文化都发生了剧烈的变化。而史学的发展变革也是社会转型的表现之一。与唐代前期相比，中晚唐史学比较突出的特点是出现了大量的史论。这些史论集中反映了在唐代社会变革时期人们对社会历史发展与史学自身的认识与探究，其中既有历史发展的动因与盛衰之变、社会制度的历史发展、历史文化的认同观念等历史观问题，也包含了史家修养、历史编纂的方法和形式、史学的社会功用与学术价值等史学观问题。

论文绪论部分阐述了中晚唐史论的研究意义和研究现状，对研究方法与创新点作出了说明。

第一章分析了中晚唐时期史论思想形成的社会环境与学术文化背景。在政治上，安史之乱以后，出现了宦官专权、朋党之争、藩镇割据与民族矛盾激化等社会问题。人们希望通过总结和评述历史经验来解决现实政治困境，从而促进了史论的发展。在思想文化方面，儒学思想的复兴、经学思想的新变以及古文运动的蓬勃发展对儒学道统认同观念、史学方法论、经史关系与疑古辨伪等史论思想产生了深刻影响。就史学本身而言，在安史之乱后官方修史机制得到了一定的恢复与修缮，与此同时，政治权力对官方修史活动的干预也在不断加强，从而影响到史家的直书观念。在历史编纂方面，通史体裁受到史家的重视，制度史、历史地理和民族史的撰述也呈现勃兴的趋势，这与中晚唐史论通识化特点的形成，以及制度因革论、历史地理观、民族史论的发展都有着密切的联系。

第二章论述了中晚唐史论对历史发展的动因与盛衰之变的探究。关于历史发展的动因，中晚唐史论详细探讨了天人关系在历史发展中的地位和作用，其思想观点反映出天人感应观念的式微，“天”的神秘色彩日趋淡化，哲理化的思想内涵愈加突出。关于历史盛衰之变，中晚唐史论深入探讨了君、臣、民三者之关系对历史盛衰的影响，强调时势在历史发展中的重要性，注重对盛衰之理的总结。

第三章论述了中晚唐史论中的社会发展观与制度变革思想。中晚唐史论辨析了“德”与“力”对社会制度起源的决定作用，突出了社会统治职能中食货与教化的重要意义，对质文递变的制度因革理论以及制度发展的古今关系也作了更加深入的阐释，强调了制度变革的必要性。而且，中晚唐的社会制度发展论还集中体现在禅让史论与封建论这两方面。其中，禅让史论不但强化了人们对尧舜禅让的信仰与认同，而且从道义和历史发展形势两个方面阐述了从禅让到世袭之转变的合理性；封建论则从古今历史发展之势的角度分析了封建、郡县的利弊得失，并且从现实政治出发强调了郡县制的历史价值。

第四章论述了中晚唐史论的历史文化认同观念的发展。第一，中晚唐时期的正统论追溯并考辨了上古帝王世系，提出了以“大一统”思想为核心的正闰评判标准，并且否定了武周政权的正统性，体现出当时的统治者和史家对唐王朝政权合法性的认同与强化。第二，韩愈、李翱等学者的道统论构建了系统化的儒学思想传承体系，推进了历史文化的道统认同意识的发展，强调了儒学思想在历史文化发展中的主体性地位。第三，中晚唐时期的史论还反映了历史文化发展中的氏族观、历史地理观与民族观。其中，以血缘传承为核心的氏族史观日益淡化，氏族对历史文化的传承意义则凸显出来；对疆域历史发展以及都邑地理条件和历史地位的探讨，体现了历史发展的地域认同观念；而民族史论强调了华夏民族在历史文化发展中的主体地位，体现出历史文化的民族认同意识的加深。

第五章论述了中晚唐史家职责与修养论的演变，以及历史编纂理论的发展。关于史家职责与修养论，中唐以后，传统的史家直书精神受到了政治斗争的冲击，史家在史论中强调坚守“直道”的同时又提出“中道”思想。中晚唐史家修养论继承和发展了刘知幾的史才三长说，对史家才、学、识的具体内涵作了进一步的阐述，并且突出了史家的道德品质的重要性。关于历史编纂论，首先，在历史编纂方法上，中晚唐史论强调了褒贬笔法的重要性，并且提出了“从权”、“原情”、“公是公非”、“由中庸以入尧舜之道”等史笔褒贬的原则。其次，在史书编纂形式上，中晚唐史论系统论述了编年、纪传二体的特点，强调史书体裁的选择要突出史家的作史之义；改变了此前史家反对文章入史之说，强调了载文入史的重要意义；探讨了历史叙事的价值以及历史叙事中文与理、华与实、繁与简的关系。

第六章论述了中晚唐史学的功用与价值论。关于史学的社会功用，中晚唐史论体现出历史鉴戒思想的丰富发展，注重从长时段的历史发展中总结经验教训，重视对本朝历史的反思。而且，中晚唐史论突出了史学经世致用的资政价值与道德教化意义，主张从历史经验中系统总结为政之理，强化了史学彰善瘅恶以维护社会纲常伦理的作用。关于史学的学术价值，主要论述了中晚唐的经史关系论和疑古辨伪学说，二者都体现出中晚唐史学求真与求道的双重价值。

结语部分系统总结了中晚唐史论的思想内容，着重论述了中晚唐史论的通识化、义理化以及注重史学与社会关系等特点，并且分析了中晚唐史论的学术价值和历史影响。

The middle and late Tang was the social transformation period of the Tang Dynasty. During this period, politics, economic, ideology and culture changed drastically. The development and transformation of historiography was also one of the aspects of social transformation. Compared with the early period of the Tang Dynasty, the more prominent feature of the middle and late Tang historiography was the emergence of a large number of historical comments. These historical comments typically reflected people’s understanding and exploration of the development of history and historiography during the social transformation period of the Tang Dynasty. These historical comments reflected historical views at that time,such as historical motivations,rise and fall of dynasties in history, the historical development of political systems, as well as the notions of historical and cultural identity.They also explained historiography views which included the qualities of historians, the methods and forms of historical compilation, and the social and academic value of historiography.

The introduction of the thesis expounds the origin and significance of this subject, summarizes and briefly analyzes research status, and explains the research method and innovations.

The first chapter analyzes the social environment and cultural background of the formation of historical thoughts in the middle and late Tang Dynasty. On the political front, after the Anshi Rebellion, social crisis such as the dictatorship of eunuchs, cliques struggle, the separatism of military governorship and ethnic conflicts emerged. People hoped to solve the political dilemma by summarizing and commenting on historical experiences, which promoted the development of historical comments. In terms of ideology and culture, the revival of Confucianism, the new changes in Confucian classics studies, and the vigorous development of the ancient prose movement had a profound impact on orthodoxy of Confucianism, the methodology of history, the relationship between classics and history, as well as the distinguishing the authenticity of classics. The official historical mechanism was restored to a certain extent after the Anshi Rebellion. At the same time, the intervention of political power in official historical activities was continuously strengthened, which affected the historian's view of historical writing authenticity(Zhi Shu). In terms of historical compilation, the general history genre was valued by historians, and the writings of institutional history, historical geography and national history also showed a booming trend. This was related to the formation of the generalized characteristics of historical comments, as well as the comments of institutional evolution,historical geography, and ethnic history in the middle and late Tang Dynasty. 

The second chapter discusses the historical comments of the middle and late Tang Dynasty on the motivation of historical development and the exploration of the dynasties’rise and fall in history. Regarding the motivation of historical development, the historical comments of the middle and late Tang Dynasty discussed the role of the relationship between heaven(Tian) and human in the historical development,which reflected the decline of the concept of the interaction between heaven and human, and the fadeout of heaven(Tian)’s mystery,as well as the highlight of its philosophical characteristic. Regarding the dynasties’rise and fall in history, the historical comments of the middle and late Tang Dynasty deeply explored the influence of the relationship between emperors, ministers and the people on the dynasties in history.They also emphasized the importance of the current situation(Shi Shi) in historical development, and paid attention to summarizing the theories of the historical rise and fall.

The third chapter discusses the thoughts of social development and systemic reform in historical comments of the middle and late Tang Dynasty. The historical comments distinguished the decisive role of morality and force on the origin of the social systems.They highlighted the important significance of economy and etiquette in the function of social governance, and contributed to the theory of alternation between modesty(Zhi) and literaryism(Wen),as well as the development of the systems in ancient and modern times,which emphasized the necessity of systemic changes. Moreover, the social systems development comments of the middle and late Tang dynasties was also concentrated in two aspects: the historical view of abdication(Shan Rang) and feudalism. The historical view of the abdication in the middle and late Tang Dynasty not only strengthened people’s belief and identification with Yao and Shun’s abdication, but also expounded the rationality of the transition from abdication to hereditary system in two ways: morality and historical development. The feudal comments in the middle and late Tang dynasty analyzed the pros and cons of feudalism and the prefectures and counties from the perspective of the historical development trend of ancient and modern times, and emphasized the historical value of the prefecture system from the perspective of realistic politics.

The fourth chapter discusses the development of historical and cultural identity concepts in the historical comments of the middle and late Tang Dynasty. First, the orthodoxy in the middle and late Tang dynasty traced back and examined the lineage of the ancient emperors, proposed the judging standard of orthodox with the idea of "great unification" （Da Yi Tong）as the core, and denied the legitimacy of the Wu Zhou regime, reflecting the rule of the time. Authors and historians recognized and strengthened the legitimacy of the Tang Dynasty regime. Secondly, Han Yu, Li Ao and other scholars' Confucianism comments constructed a systematic Confucianism inheritance system, promoted the development of historical and cultural identity of Confucianism, and emphasized the subjective status of Confucianism in the development of history and culture. Third, the historical comments in the middle and late Tang Dynasty also reflect the views of clan, historical geography and ethnic history in the development of historical culture. Among them, the concept of clan history centered on the inheritance of blood is increasingly weakened, and the significance of the clan's inheritance of history and culture is highlighted. The discussion of the historical development of the territory and the geographical conditions and historical status of the capital in the historical comments of the middle and late Tang reflects the concept of regional identity of historical development. The comments of national history emphasizes the dominant position of the Chinese nation in the development of history and culture, and reflects the deepening of the national identity consciousness of history and culture.

The fifth chapter discusses the evolution of the spirit of straight writing (Zhishu)  and the comments of historian's quality, as well as the development of historical compilation comments in the middle and late Tang Dynasty. Regarding the spirit of straight writing and the comments of historian's quality, after the mid-Tang Dynasty, the traditional straight writing spirit was impacted by political struggles. Historians emphasized sticking to the "straight way"(Zhi Dao) in the historical comments and put forward the "medium way"(Zhong Dao) thought at the same time. The comments of historian's quality in the middle and late Tang inherited and developed Liu Zhiji's comments of historians, further expounding the specific connotation of historians' talents and insights, and highlighting the importance of historians' moral qualities. Regarding the comments of historical compilation, first of all, in the method of historical compilation, the historical comments of the middle and late Tang Dynasty emphasized the importance of commendatory and derogatory writing,and proposed "Weight the advantages and disadvantages"(Quan), "pursue emotions"(Yuan Qing), "public right and wrong"(Gong Shi Gong Fei), and "from the moderation into the Dao of Yao and Shun"(You Zhong Yong Yi Ru Yao Shun Zhi Dao) and other historical writing principles. Secondly, in the form of history books compilation, the history comments of the middle and late Tang Dynasty systematically discussed the characteristics of chronology and chronicle biography, emphasizing that the choice of genre of history books should highlight the meaning of historians in history; it changed the previous historian's objection to the entry of articles in history, emphasizing It discusses the important significance of writing articles into history; discusses the value of historical narrative and the relationship between Chinese and rational, flowery and real, complex and simplified in historical narrative.

The sixth chapter discusses the social function comments and academic value comments of the historiography of the middle and late Tang Dynasty. Regarding the social function of historiography, the comments of history in the middle and late Tang reflected the rich development of historical admonition thinking, focusing on summing up experiences and lessons from the long-term historical development, and attaching importance to the reflection on the history of the dynasty. Moreover, the comments of history in the middle and late Tang highlighted the political value and moral  significance of historiography, advocated systematic summarization from historical experience as a political rationale, and strengthened the role of historiography to clarify the good and evil in order to maintain the social ethics. Regarding the academic value of historiography, the comments of the relationship between classics and history and the thoughts of suspicious of ancient history and discerning falsehood in the middle and late Tang Dynasty reflected the dual value of seeking truth and seeking morality.

The conclusion of the thesis systematically summarizes the ideological contents of the historical comments of the middle and late Tang, focusing on the generalization, rationalization of the historical comments of the middle and late Tang, and the emphasis on the relationship between historiography and society, and analyzes the academic value of the historical comments of the middle and late Tang And historical influence.