To understand nature, physicists have attempted to construct minimalistic laws to describe varied phenomena. In history of science, there have been successes in this direction-— Maxwell’s unification of EM laws, Unification of forces, etc. However, the world appears to be quite complex, and there is a school that believe that not everything can be derived from microscopic laws. It is possible that different layers of nature have their own laws, thus nature’s laws may be hierarchical.
I will illustrate these observations using three examples: Phase transitions, Dynamic pressures in hydrodynamics, and Kolmogorov's theory of turbulence.