Life depends on the polarity between activity and receptivity.
This maintains tension, every adjustment of which manifests itself as change,
a process in life.
If this state of tension, this potential, were cease to exist, there would no longer be a criterion for life
Life could no longer express itself.
On the other hand, these polar oppositions, these tensions, are constantly being generated by the changes inherent in life.
If life should cease to express itself, these oppositions would be obliterated by progressive entropy, and the death of the world would ensue.’
  The l Ching.