Time

From about 500 to 200 B.C.E. several Chinese thinkers conceived time abstractly and without reference to gua systematics. Passages in Zhuangzi, Huainanzi, and Shuowen jiezi (a second-century C.E. lexicon) drew upon extant terms connoting "time," linking them with categories for space and motion: these terms included shi (season, historical moment), yu (spatial expanse, first delineated as the area of a roof's perimeter, later "the four directions plus up," and, for Zhuangzi, "reality without anything in it [the void-expanse]"), and zhou (the cyclic, expected return of any moving thing; for Zhuangzi, "what goes on extensively but has no beginning or end"); hence the binome yuzhou—limitless expanse conjoined with cyclical return. The oldest terms were not intentionally abstract, but pointed to social time, timeliness of action, and spatiality as products of motion and change.

When the oldest Zhuangzi passages were created (probably c. 300 B.C.E.), logico-analytic debates were popular, and we find statements of a certain Hui Shi, who states the paradox, "One sets out for Yue today, but arrives in the past." The authorial voice, Zhuangzi, ridicules Hui Shi's mode of knowledge, yet the much later (fourth century C.E.) commentary takes it seriously, arguing that the "setting out" and the "arriving" (abstractly analogized as "knowing" and its known "entity") are like facing mirrors, which make a continuum of reflection: thus the "knowing" about "setting out for Yue" engages simultaneously with its dyadic partner, the "arriving."

Equally striking was the Mohists' approach to time. Early Mohists (roughly 400–350 B.C.E.) were an influential community dedicated to knowledge, ethics, and supplying political-military services to regional courts. Their writings were poorly transmitted and taken up only rarely by later Chinese scholars. The brilliant reconstruction of the jumbled extant version of the Mohist Canon by A. C. Graham has shown that time was articulated with brief declarations of such notions as light, weight, speed, and geometric axioms. One logical premise concerns "Duration: what fills out different times. Extension: what fills different locations." The later Mohists (about 300 B.C.E.) blended their own thoughts into the Canon and distinguished between times with and without duration: "Of times in a movement some have duration, others do not have duration. The beginning does not have duration."