The primary themes and argumentative strategies in Zhuangzi's philosophy bear some resemblance to those in the Daodejing. The philosophy of Zhuangzi is expressed in a text bearing his name. However, like the Daodejing, sections of the Zhuangzi (or Chuang-Tzu) were composed by different authors and the compiled text contains writings collected over a period of time. In the case of the Zhuangzi, the fragments date from between the fourth to the second centuries BCE (Graham 2003a:58), and debate persists concerning when particular sections might have been written. Traditionally, the two texts, the Daodejing and Zhuangzi, had been grouped as texts belonging to one tradition, the Lao-Zhuang tradition. There was also some consensus that the Daodejing was composed earlier than the Zhuangzi and, as they stand in that relation, the Daodejing is a less sophisticated text while the Zhuangzi represents a mature, developed Daoism. For example, Wing-tsit Chan notes: