49. Zhang Zai sets up this concept of qizhi 氣質 in opposition to that of “nature of Heaven and Earth,” which denotes an original and pure nature (e.g., nature as defined by Mencius). See qizhi in Zhang Zai Ji, 265–270; See also Jinsilu Jijie, 2: 69. Zhang uses the term xing of “nature” in three different ways: (1) as the character or quality of a specific object, like warmth or consistency; (2) as the original nature of man; (3) as the common nature of men and all other beings in the universe. See also Jiang and Zhu, Zhongguo Lishi Shang de Renxing Lun, 126–130.

50. Zhang Zai Ji, 23 (Zhengmeng, 6: 20–24).

51. Zhuzi Yulei, 4: 79-81; 55: 1307.

52. Ibid., 4: 69.

53. Ibid., 4: 66.

54. As reported in Zhang Zai, only destiny, life, and death are independent of the moral sphere and thus cannot be changed by man. See Chan Wing-tsit, “The Neo-Confucian Solution of the Problem of Evil,” 773–791. The Cheng brothers inherited this dichotomy and contrasted “heavenly-infused nature” (tianming zhi xing 天命之性) with “nature received by psychophysical energy” (qibing zhi xing 氣稟之性). Cheng Yi makes a clear distinction between these two natures, which he calls endowments of xing and cai respectively. While the former is identified with supreme principle, related to Heaven and always morally good (性即理也 […] 性出於天 […] 性則無不善), the latter originates from psychophysical energy, and accordingly can be either clear or turbid, good or evil (才出於氣。氣清則才清，氣濁則才濁。才則有善有不善 […]); Jinsilu Jijie, 1: 22 and 24). Similarly, Cheng Hao refers to the psychophysical energy as something that can be good or bad from childhood; furthermore, he speaks of human nature as received at birth in its primordial state of stillness, but as such also immediately mixed with the said energy (Jinsilu Jijie, 1: 13–14). See Santangelo, Zibuyu, 77–78.

55. Adler, “Chance and Necessity,” 181.

56. “人性無不善。雖桀紂之為窮凶極惡，也知此事是惡。但則是我要恁地做，不奈何，便是人欲奪了” (Zhuzi Yulei, 95: 2420, and Zhuzi Quanshu 朱子全書, in Siku Quanshu, Zibu 子部, Rujialei儒家類, Yuzuan Zhuzi Quanshu 御纂朱子全書, juan 42; cf. Zhuzi Yulei, 59: 1375).

57. Anticipating the representation by Saint Paul’s Epistle to the Romans that will be quoted in its entirety in the following section, we can find relevant analogies and differences with Zhu Xi’s metaphor. In both cases the subject is a battlefield, and the conflict between their own nature and desires (as addressed in Zhu Xi) finds its nearest equivalent in the spiritual