“Compared to physics, it seems fair to say that the quantitative success of the economic sciences is disappointing. Rockets fly to the moon, energy is extracted from minute changes of atomic mass without major havoc, global positioning satellites help millions of people to find their way home. What is the flagship achievement of economics, apart from its recurrent inability to predict and avert crises, including the current worldwide credit crunch? Why is this so? Of course, modelling the madness of people is more difficult than the motion of planets, as Newton once said [c.1690]. But the goal here [see: social ideal gas law] is to describe the behaviour of large populations, for which statistical regularities should emerge, just as the law of ideal gases emerge from the incredibly chaotic motion of individual molecules.

The "perfect economic system" cartoon from Bouchaud's 2008 article “Economics Needs a Scientific Revolution”. [2]

Classical economics is built on very strong assumptions that quickly become axioms: the rationality of economic agents (the premise that every economic agent, be that a person or a company, acts to maximize his profits), the ‘invisible hand’ (that agents, in the pursuit of their own profit, are led to do what is best for society as a whole) and market efficiency (that market prices faithfully reflect all known information about assets), for example. An economist once told me, to my bewilderment: “These concepts are so strong that they supersede any empirical observation.” As economist Robert Nelson argued in his book, Economics as Religion (Pennsylvania State Univ. Press, 2002), the marketplace has been deified.

Physicists, on the other hand, have learned to be suspicious of axioms. If empirical observation is incompatible with a model, the model must be trashed or amended, even if it is conceptually beautiful or mathematically convenient. So many accepted ideas have been proven wrong in the history of physics that physicists have grown to be critical and queasy about their own models. Unfortunately, such healthy scientific revolutions have not yet taken hold in economics, where ideas have solidified into dogmas. These are perpetuated through the education system: students don’t question formulas they can use without thinking.”

“Whereas the simple Curie-Weiss mean-field approximation for homogenous systems is well known and accounts for interesting collective effects, its heterogeneous counterpart is far subtler and has only been worked out in detail in the last few years. It is a safe bet to predict that this powerful analytical tool will find many natural application in economics and social sciences in the years to come.”

— Jean-Philippe Bouchaud (2009), “The (Unfortunate) Complexity of Economy” [3]