In addition to his Memorial on the Buddha’s Bone, Han Yu also wrote essays on the topic of Confucian philosophy, one of which, The Origin of the Dao, made a reasoned distinction between Confucianism on the one hand and Buddhism and Daoism on the other, characterising the Dao of Buddhism and Daoism alike as internal and subjective, whereas the Dao of Confucianism was public and objective. His own traditionalist stance is clear from passages like the following:
Now what do we mean when we talk of ‘the teaching of the former Kings’? Their extension of love may be called Ren; their practice and approbation of Ren may be called Yi; conducting themselves on this basis may be called Dao; being self-sufficient without dependency on externals, may be called De. Their literature was the Odes, the Histories, the Book of Changes and the Spring and Autumn Annals; their laws were the Rites, Music, Punishments and Government administration; their populace comprised scholars and soldiers, farmers, artisans and tradesmen; their relationships were between ruler and minister, father and son, teacher and pupil, guest and host, brothers, and husband and wife. Their clothing was of hemp and silk, their dwellings were palaces and houses; their food was cereals, rice, fruit, vegetables, fish and meat; what they practised as Dao was straightforward and enlightened, and their teaching was simple to achieve.… What sort of Dao was this Dao? I say it is what I call Dao. It does not resemble what the Buddhists and Daoists call Dao. Yao took this Dao and transmitted it to Shun; Shun transmitted it to Tang; Tang transmitted it to the rulers of Zhou; the rulers of Zhou transmitted it to Confucius; Confucius transmitted it to Mencius. But at Mencius’ death, it was not able to be transmitted further. Xünzi and Shang Yang confused it, their words on the subject were not accurate. Before the time of the Dukes of Zhou, the rulers were superior men, hence their actions succeeded; since that time, inferiors became ministers, hence mere words proliferated.
This reassertion of Confucian values is one aspect of the rethinking of the tradition that was going on in ninth-century Tang China. There were, however, other developments, which looked at the philosophical problems of the age in a broader light. One of the Tang philosophers in this area was a man named Li Ao. He was looking for a way in which Confucianism could accommodate the ‘otherness’ implicit in Buddhism and Daoism, and in one passage he says:
How can a Sage be devoid of feeling? He is silently immovable; he arrives at his goal without travel, he is divine in his silence; he is enlightened without casting light. In acting, the Sage participates with Tian and Di; in his changes he accords with Yin and Yang. The Sage comprehends the feelings, but he is not subject to feelings.
Here Li Ao is discussing the subjective aspects of the sage’s experience, and the whole of the essay from which the extract is taken is an exploration of how the sage must put feelings on one side in order to understand the natural order of things. This sense of detachment, as well as the concepts in the extract about, for example, arriving without travelling, show clearly that Li Ao was strongly influenced by Buddhist and Daoist values, and was trying to show how these subjective quantities could be expressed within a Confucian framework of understanding.
Han Yu’s exposition of the fundamentals of Confucianism and Li Ao’s exploration of how the kind of values which characterised Buddhism and Daoism made a key contribution to the development of philosophical thought that would take place in the Sung Dynasty, which came to power following the final collapse of the Tang regime and ruled substantially unchallenged from 960 to 1126 and then, after north China was seized by the Mongols, from 1127 to 1279 as the ‘Southern Sung’ Dynasty.
By the beginning of the Sung, Confucianism, Daoism and Buddhism all had their followings, and had set up permanent institutions by which their respective aims were to be fulfilled. Even the despised Legalism was implicit in what had now become the typical Confucian administration of the Chinese Empire. With all these strands pulling in different directions, attempts were made to promote a new form of unified philosophy that would be basically Confucian in nature, but would incorporate what we might nowadays call the ‘metaphysical’ aspects of Buddhism, Daoism and occultism.
The key item in this rebuilding of Confucianism was the concept of Dao, and its transmission from legendary times according to the account given by Han Yu and quoted above. In Chinese, the scholars who were involved were called the ‘Dao Xue Jia’ – literally, ‘the experts in studies of the Dao’. This ‘Dao Xue’ is referred to in translation as neo-Confucianism, and its practitioners as neo-Confucians. Early in the Sung Dynasty the neo-Confucian movement comprised two main schools established respectively by two brothers from Henan province, Cheng Hao (1032–85) and Cheng Yi (1033–1108). The younger brother, Yi, founded the so-called School of Principles, and Hao established the School of Mind.
The central neo-Confucian figure in the Sung is Zhu Xi (1130–1200). He took over the development of the School of Principles, and brought it to a stage where it was the predominant school of neo-Confucian philosophy. Zhu Xi himself was a famous historian, a great commentator on the newly rehabilitated Confucian Classics, a renowned philosopher and a minor statesman. Cheng Yi’s school takes its name from the character 
(li, ‘principle’), and Zhu Xi’s idea was that all things have their metaphysical principle, which is then embodied in the physical things themselves. We may perhaps think of this li of a thing as a conceptual bundle of all the basic attributes of that thing. Although one might be tempted to draw a parallel with the ‘forms’ of the ancient Greek philosopher Plato, however, the Chinese turned out to be much more interested in the application of principles to human nature and society. So, for example, Zhu Xi used his concept of li to justify Mencius’ claim that human nature is intrinsically good. He argued that the li of Man is pure, and so can be seen as the source of the basic virtues of humanity, including ren. However, the embodiment of this li in a particular individual is affected by the less-than-perfect nature of the individual and may need to be restored by education to recover its own purity. Self-cultivation also plays its part in the transformation of the human li, and may lead to an instant of sudden, Zen-like enlightenment.
The achievement of Zhu Xi and others in developing the neo-Confucian philosophy cannot be underestimated. The neo-Confucian synthesis gave the formal Confucianism of Han Yu the resilience it needed to provide an acceptable account of the human condition, with its need for metaphysical values, while retaining the authority of legend, antiquity, the Zhou rulers, Confucius and Mencius to support a state system of Confucian administration. Indeed, the neo-Confucian synthesis was to provide the central philosophy of successive Chinese administrations down to the twentieth century.