ABSTRACT Recent scholarship on the philosophy of time in pre-Qin Daoist thought has not yet produced a thorough examination of dao’s relationship to time. This essay resolves this omission through a systematic study of the concept heng 恒 in pre-Qin Daoist literature. While principally expressing the ‘constancy’ of dao, heng also significantly presupposes dao’s ability to change. This change is characterized in the texts as a cyclical movement of ‘return’ and identified with the universe’s circular metanarrative of generation and reintegration. The essay turns to examine pre-Qin Daoist literature’s use of primal wu 無 metaphors to describe dao. It concludes that they present dao as undifferentiated infinitude, liberating dao as heng from the tense structure of past-present-future that divides life in time. These metaphors further associate the movement of dao with the flow of time, reformulating time’s relentless ever-greater advancement into an endless cycle of creative transformation.