The importance of the 'li' was emphasised by Confucius not only because of the evident material benefits that would derive from their correct application, but above all in so far as they provided a model of life which conformed to a celestial design.
As the name implies, it was a period of disunity, when several different states were warring with each other to determine who would gain control of all of China and found a new dynasty. The sages built on the accomplishments of previous sages, added their own contributions, and now Xunzi believes the process is basically complete: we know the ritual principles that will produce a harmonious society.
If for a single day one could submit to the observance of the rites through disciplining himself, then the whole world would find virtue. Using the piano analogy, the scholar has made up his mind to study the piano and is practicing basic scales.
Hence, Xunzi wrote that Confucian teachings allow people to satisfy both the demands of ritual and their desires, when the alternative is satisfying neither. In Xunzi's view, the best thing to do is understand what Nature does and what humanity does, and concentrate on the latter.
Of course, this developing 'ren' has not reached the highest level of moral excellence.