y Han Yue: some
people have a good, others a neutral, and still others a bad nature;
therefore, not everybody can become a leader. The Neo-Confucianists,
especially Ch'eng Hao (1032-1085) and Ch'eng I (1033-1107), tried to
find the reasons for this inequality. According to them, nature is
neutral; but physical form originates with the combination of nature
with Material Force (_ch'i_). This combination produces individuals in
which there is a lack of balance or harmony. Man should try to transform
physical form and recover original nature. The creative force by which
such a transformation is possible is _jen_, love, the creative,
life-giving quality of nature itself.

It should be remarked that Neo-Confucianism accepts an inequality of
men, as early Confucianism did; and that _jen_, love, in its practical
application has to be channelled by _li_, the system of rules of
behaviour. The _li_, however, always started from the idea of a
stratified class society. Chu Hsi (1130-1200), the famous scholar and
systematizer of Neo-Confucian thoughts, brought out rules of behaviour
for those burghers who did not belong to the gentry and could not,
therefore, be expected to perform all _li_; his "simplified _li_"
exercized a great influence not only upon contemporary China, but also
upon Korea and Annam and there strengthened a hitherto looser
patriarchal, patrilinear family system.

The Neo-Confucianists also compiled great analytical works of history
and encyclopaedias whose authority continued for many centuries. They
interpreted in these works all history in accordance with their outlook;
they issued new commentaries on all the classics in order to spread
interpretations that served their purposes. In the field of commentary
this school of thought was given perfect expression by Chu Hsi, who also
wrote one of the chief historical works. Chu Hsi's commentaries became
standard works for centuries, until the beginning of the twentieth
century. Yet, although Chu became the symbol of conservativism, he was
quite interested in science, and in this field he had an open eye for
changes.

The Sung period is so important, because it is also the time of the
greatest development of Chinese science and technology. Many new
theories, but also many practical, new inventions were made. Medicine
made substantial progress. About 1145 the first autopsy was made, on the
body of a South Chinese captive. In the field of agriculture, new
varieties