to be identified.
Walras sets himself the largest task. He recognizes that if an economy is a set of markets, then if a single market is out of equilibrium, all markets will be thrown out of equilibrium, because they are all interlinked. The income you draw from one market is what you spend in another. Thus, change the demand and supply represented by a single price, and every other price must adjust to meet the rippling changes in all other supplies and demands (Canterbery, 2001, pp. 135-36).
Moreover, our wants, which the classicists regarded as indefinite, are in fact limited, at least once specifics are considered.
Jevons writes (quoted in Canterbery, 2001, p. 125) that
As the quantity of any commodity, for instance, plain food, which a man has to consume, increases, so the utility or benefit derived from the last portion used decreases in degree. The decrease of enjoyment between the beginning and end of a meal may be taken as an example.
The point of marginal utility is reached with the last bite of food that we are willing to pay to eat, after which out attention will turn to other things. Karl Menger uses this approach to propose a hierarchy of wants (Canterbery, 2001, p. 125. In practice, consumers no doubt shift progressively, becoming more interest in buying clothes as their food demand is progressively met, but Menger's principle still applies.
The elements of marginal cost, demand, and price allow the neoclassicists to fill in the behavior of individual consumers and firms. Their behavior is no longer simply a presumed dead hand operating on the macroeconomic level, but instead constantly adjusts in response to their particular circumstances. The economic wolves, says Heilbroner (1999, p. 172), are reduced to sheep. The resulting picture of the economy as a whole is thus more fluid and dynamic. In fact, it became so dynamic as to challenge the mathematical tools then available. ...