If we call a dynamic system that forms itself from the interaction of countless elements a "complex system," then the universe, matter, life, and society are all complex systems. The "science of complex systems," which points to the new direction of science in the 21st century, reveals such a world. This paper takes out the coincidence, non-determinism, and irreversibility of the world and criticizes modern science, which simplifies nature by the law of cause and effect and views it deterministically.