_Heaven_ signifies night and day, cold and heat, times and seasons.
The commentators, I think, make an unnecessary mystery of 陰陽.
Thus Mêng Shih defines the words as 剛柔盈縮 “the hard and the
soft, waxing and waning,” which does not help us much. Wang Hsi,
however, may be right in saying that what is meant is 總天道 “the
general economy of Heaven,” including the five elements, the four
seasons, wind and clouds, and other phenomena.