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 Maxwells 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 natures laws may be hierarchical.
I will illustrate these observations using three examples: Phase transitions, Dynamic pressures in hydrodynamics, and Kolmogorovs theory of turbulence.
Mahendra Verma received his B. Tech. degree from IIT Madras, and Ph.D. degree from University of Maryland, College Park. Presently he is a Professor at the Physics Department of IIT Kanpur, India. He is recipient of Swarnajayanti fellowship and Dr. A.P.J. Abdul Kalam Cray HPC Award, and is author of the books Introduction to Mechanics and Physics of Buoyant-flows. Mahendras research interests include turbulence, nonlinear dynamics, high-performance computing, and non-equilibrium statistical physics. He and his group have developed a spectral code TARANG that can simulate variety of fluid flows.