difference between economic and accounting profit Value theory of the many contradictions and arguments, essentially derives from the different definitions of value, originated in the people for the different understanding of the concept of value, value, from the perspective of physics can put the theory of value based on the foundation of natural science, with a high degree of accuracy, objectivity and rationality, so that the value theory of widespread vagueness, subjectivity and ambiguity naturally are addressed. As social things all the movement and the change of value relation is in essence the motion and change, so the value theory is the foundation of social science theory, if the value theory is built on the basis of natural science, can greatly promote the fusion and unity of the social science and natural science, but also make the social science become subservient to the natural sciences. Famous British economist hicks and others argue that the above theory did not consider the factor of income, and therefore unable to determine the level of interest rates, in 1937, and puts forward the is-lm model on the basis of general equilibrium theory. It establishes a theory of interest rates and income at the same time that the four factors of savings and investment, money supply and monetary demand interact. There were two opposing views of development in the 19th century. A push performance degradation is based on the second law of thermodynamics system, it argues that, due to the dissipation of energy, the world tends to be weak, the universe tends to "heat death", the structure of the retreat, disorder tend to the maximum, the whole world over time and the process of dying; Another is based on Darwin's theory of evolution of the evolution of the concept system, it points out that social evolution is the result of the increasing division of species, the evolution and increased, structure complex and orderly, and constantly reinforced by functional evolution, all nature and human society are to develop more advanced, more orderly organization structure. Julie Palmer, a retail expert at Begbies Traynor, said retailers faced a particularly disappointing deal in the weeks following the apparent success of "black Friday" at the end of November.