Hiding the truth

In their wonderful (and provocative) PNAS article, The Theory of Everything, Laughlin and Pines introduced the term protectorate to describe the insensitivity of higher level laws (organising principles) to the details of lower level laws. For example, the laws of thermodynamics are the same regardless of whether the microscopic dynamics of the constituent particles is quantum or classical. Universality in the theory of continuous phase transitions is another important example. Near the liquid-vapour critical point the critical exponents are independent of the chemical composition of the system or of the interatomic forces involved.