As with all sciences, the study of strategy studies the operation of natural systems. All such systems exist as a balance of forces. Sun Tzu abstracted this balance as emptiness and fullness, basing his vision on the concept of complementary opposites that is known as the Chinese concept of yinyang. The dynamics of nature continually shift the balance of forces, but the universe doesn't fly off in chaos or freezing into stasis because of this mainspring built into nature. While we humans can leverage the forces of nature, we cannot control them.