AbstractWe discuss difference between the classical and quantummethods of description of Nature in terms of fundamentalobservables related to the dynamical symmetry group of theHilbert space and quantum fluctuations, specifying their mea-surement. We show that the total amount of quantum fluc-tuations of fundamental observables can be used to measurethe “remoteness” of quantum states from “classical reality”provided by the choice of observables in terms of c-numbers.The proposed picture is more general than Bell’s approach todefinition of “classical reality”.