Wei Jin Astronomers' Hermeneutics of the Calendrical Classics and Astronomical Heavens

John B. Henderson
Louisiana State University

It is well known that the major Chinese philosophical traditions and their hermeneutics underwent radical changes during the Wei-Jin period. It is perhaps not so widely recognized that significant changes also took place in the ways that astronomers of that period interpreted both the calendrical classics, ranging from the Spring and Autumn Annals to the Taichu calendrical system promulgated under the Former Han, and the heavenly text (tianwen ??) that was the original object of calendrical exegesis. With respect to the former, astronomers of the Wei-Jin-Nanbeichao placed the calendrical classics within larger historical schemas, problematizing and debating such issues as the alleged fall from astronomical antiquity with the decline of the Western Zhou, Confucius' attempted reform of astronomy and the calendar in the Spring and Autumn Annals, and the position of the classical/Han calendrical systems within the larger tradition. Although earlier astronomical authorities, including Sima Qian, had articulated a rudimentary astronomical Daotong (transmission of the Way), the post-Han astronomers developed a more historical hermeneutics of the classics of their tradition.

Second, astronomers of the Wei-Jin-Nanbeichao reinterpreted the heavenly text, as well as the astronomical classics, in part by questioning classical/Han cosmological and numerological schemas in the light of the growth of empirical astronomical knowledge. In view of such new discoveries as the inequalities of solar and lunar motion and the precession of the equinoxes (or "annual difference" between the tropical and sidereal years), some post-Han astronomers both challenged classical numerological schemas that were supposed to generate such astronomical periods and constants as intercalation ratios, as well as questioned the possibility that any calendar could precisely and perpetually interpret the elusive, subtle, and evolving heavenly text Unlike commentators in the Confucian tradition who often assumed the possibility of an eternally valid classical hermeneutics, some Wei-Jin astronomers and their successors assumed that their hermeneutics of the heavens would be relatively accurate and applicable for only a limited period of time. In contrast to the classics, the heavens evolved historically, necessitating periodic reinterpretations.

Not all the major astronomers of the Wei-Jin-Nanbeichao challenged the classical/Han hermeneutics of the heavens. Some, in fact, defended it, arguing, for example, for the perfection of ancient calendrical and astronomical calculations, supporting the numerological derivation of astronomical periods and constants, and denying the existence of historical changes in the heavenly text, such as the annual difference, which seemed to make periodic calendrical reform necessary. More than perhaps any other era in the history of Chinese astronomy, including even the more well-known period of the introduction of Western astronomy into late-Ming and early-Qing China, the Wei-Jin-Nanbeichao was an era in which the hermeneutics of both the heavens and the calendrical classics was a matter of open and vigorous debate. Even such basic issues as the authority of the ancients, the criteria of truth, and the possibility of adequate understanding were fair game, with one commentator going so far as to condemn those who would believe antiquity while doubting the present.