The market economy is akin to nature. Government intervention in the market is comparable to the destruction of the natural environment and should be avoided. Nature untouched by the human hand is great. The fury of the elements dwarfs human power. Essentially, that is the opinion of free-market advocates, who may be described as "economic ecologists."
On the other hand, Keynesian economists say the uncontrolled market is plagued by imbalances and instability. In their opinion, government intervention in the market through fiscal and monetary policies is essential to reduce unemployment, curb inflation, correct trade imbalances and tame boom-or-bust business cycles.
Free-market advocates criticize Marxist and Keynesian economists for being arrogant and abusing intelligence. They argue that it is best to leave everything to the market, while recognizing the limits of human intelligence. In their opinion, an almighty government, an imaginary goal, should not be pursued.