the-key-to-the-fields-19361

René Magritte, “La clef des champs” (1936)

Plenty of illusions are being shattered these days, such as the idea that a successful recovery from the worst economic downturn since the Great Depression would keep the incumbents in power. A combination of lost jobs, stagnant wages, and soaring inequality put an end to that illusion. Much the same has happened to American Exceptionalism.

Noah Smith has just discovered another shattered illusion: the independence of supply and demand.

equilibrium_price_and_quantity_changes_as_a_result_of_shifts_in_supply_and_demand_adapted_from_truett_and_truett_1982

Mainstream economists generally think about the world in terms of supply and demand—at both the micro and macro levels: supply and demand in the market for oranges or labor (which determine the equilibrium price and quantity), as well as aggregate supply and demand for the economy as a whole (which determine the equilibrium level of prices and output). Perhaps even more important, they think about supply and demand as acting independently of one another: a shift in supply or demand in individual markets (which lead to changes in equilibrium prices and quantities) as well as “shocks” to aggregate supply or demand in macro models (which determine changes in the equilibrium level of prices and output). The presumption is that a shift in demand (at the level of individual markets or the economy as a whole) does not cause a shift in supply (at either level), or vice versa.*

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As it turns out, the independence of supply and demand is just an illusion.

As I wrote back in 2009, it’s quite possible that at the micro level—for example, in the case of the labor market—both supply and demand are determined by something else, such as the accumulation of capital.

Thus. . .if the accumulation of capital leads to rightward shifts in both the demand for and supply of labor, wages may not increase (and quite possibly will decrease).

Therefore, supply and demand in individual markets aren’t necessarily independent.

And then, in 2013, I discussed the illusion of the independence of aggregate supply and demand.

In terms of the mainstream model, the collapse of aggregate demand leading to the crash of 2007-08 has also affected the aggregate supply of the economy—thereby shattering the illusion of the independence of the two sides of the macroeconomy. As the authors put it, “a significant portion of the recent damage to the supply side of the economy plausibly was endogenous to the weakness in aggregate demand—contrary to the conventional view that policymakers must simply accommodate themselves to aggregate supply conditions.”

Not only does the destruction of a significant portion of the future growth potential of the U.S. economy challenge the model mainstream economists use to analyze the macroeconomy and to formulate policy; it also forces us to question the rationality of a set of economic arrangements in which trillions of dollars of potential wealth (which might then be used to improve lives for the majority of the population) are sacrificed at the altar of keeping things pretty much as they are.

It represents the indictment both of an academic discipline and of economic system.

So, Smith is right: the shattering of the illusion of the independence of supply and demand means the way mainstream economists teach basic economics is fundamentally wrong.

What he forgets to mention, however, is that an economic system that is governed by supply and demand that are not independent of one another—and thus is subject to considerable instability on a regular basis, with the costs being shouldered by those who can least afford it—is also open to question.

Perhaps Tuesday’s results will serve notice that the time for challenging mainstream economics and the economic and social system celebrated by mainstream economists has finally arrived.

 

*There can, of course, be simultaneous shifts in supply and demand but the shifts themselves are considered independent of one another.

 

Comments
  1. Bruce says:

    Sraffa made a general argument to this effect in two then-famous papers back in the 1920s. Today, of course, no-one remembers.

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