Shuo Gua Zhuan Chapter3
Heaven and Earth occupy determinate positions. Mountain and Marsh communicate with their qi. Thunder and Wind excite each other. Water and Fire interact but do not shoot at each other. Among the eight trigrams, there is mutual correlation.
Recollection of the past is natural. Anticipation of the future may be artificial*. Therefore, Yi is against the idea of pre-determined fate.
* Note: What we do may be against the current to affect the natural outcome in the future. This is the positive meaning of "Yi 易".