Professor Christopher Cullen, director of the Needham Research Institute in Cambridge, gave a lecture on the characteristics of ordering and arranging historical events typical for Chinese chronology. Under the title "Astronomy and chronology in Han dynasty: some issues and debates," Culler not only discussed the way ancient Chinese scholars tried to establish the dates of past events, but also the Xia-Shang-Zhou Chronology Project, a recent attempt to get the dates of the oldest dynasties fixed.
"The Han dynasty (206 BCE - 220 CE) saw the construction of the first fully worked out systems of mathematical astronomy in China." The famous Sima Qian 司馬遷 provided a list of the generations of the early dynasties without adding dates to them, because he already did not trust his sources. "Such systems were not only expected to predict future astronomical events, but also to 'retrodict' astronomical events recorded in ancient historical sources. As a result, debates about the validity of astronomical systems inevitably involved questions of chronology." Cullen used the writings of Liu Xin 劉歆 (c. 50 BCE - 23 CE) as an example of an early chronology project which dates the fall of the Xia dynasty in 1751 BCE. The Bamboo Annals would suggest 1558 BCE, and the recent chronology project, commissioned by the P.R. of China, dated the Xia conveniently from 2070 to 1600 BCE. Personally, I prefer seeing the Xia as the mythical dynasty of which its features, let alone exact dates, we will never know. Carbon-dating has been applied to some archaeological findings, but these only give an estimate, and moreover, might not even be really Xia, but instead Shang. Besides, even if these were Xia, that would not make it a dynasty, a civilisation with an hierarchical organisation and the application of metal.
Professor Barend ter Haar had an interesting hypothesis on the Xia controversy: he suggested that the Xia and Shang existed more or less simultaneously. When a list of the generations was set up during Han, these families were named one after the other, making seem that one came before the other, which does not necessarily need to be true at all.
Under the title "Historical chronology in traditional China," ter Haar also talked about the social aspect of the literati occupied with chronology. Only a very small number of people, the literati, were able to assign astronomical signs to events, and seeing that only a handful of copies existed of, for example Sima Qian's Shiji 史記, knowledge of these chronologies was not widespread.
A fascinating knowledge object that was shown was the compass: not just a needle in the middle to pinpoint the north, already a greatly influential invention, but also the circles and categories ordered around it, namely the Heavenly Stems, the Earthly Branches, the seasons and Solar Terms, etc. Yet again, only a small percentage of the population in Chinese society knew how to operate this invention. It concerned 'cosmic time' and the theory of Qi, the energy that flows in the universe, which can be attracted to and radiated from the human body. When studying the history of Chronology, one therefore needs to be conscious of the different perceptions of time.