Keynesian economics
is the view that in the short run,
especially during recessions, economic output is strongly influenced byaggregate
demand (total spending in the economy). In the Keynesian view,
aggregate demand does not necessarily equal the productive
capacity of the economy; instead, it is influenced by a host of factors and
sometimes behaves erratically, affecting production, employment, and inflation.
The theories forming the basis of Keynesian economics
were first presented by the British economist John Maynard Keynes in his book, The General Theory
of Employment, Interest and Money, published in 1936, during the Great
Depression. Keynes contrasted his approach to the 'classical' (more commonly 'neoclassical') economics that preceded his
book. The interpretations of Keynes that followed are contentious and
several schools of economic thought claim
his legacy.
Keynesian economists often argue that private
sector decisions sometimes lead to inefficient macroeconomic outcomes
which require active policy responses by the public
sector, in particular, monetary
policy actions by the central
bank and fiscal policy actions by the government, in
order to stabilize output over the business
cycle.
Keynesian
economics advocates a mixed economy – predominantly private sector,
but with a role for government intervention during recessions – and in
the developed nations served as the standard
economic model during the later part of the Great
Depression, World War II, and the post-war economic expansion (1945–1973),
though it lost some influence following theoil
shock and resulting stagflation of
the 1970s. The
advent of the global financial crisisin 2008 has caused
a resurgence in Keynesian thought.
History
Prior to the publication of Keynes's General
Theory, mainstream economic thought was that the economy existed in a state of
general equilibrium, meaning that the economy naturally consumes whatever it
produces because the needs of consumers are always greater than the capacity of
the economy to satisfy those needs. This perception is reflected in Say's Law and
in the writing of David Ricardo, which
is that individuals produce so that they can either consume what they have
manufactured or sell their output so that they can buy someone else's output.
This perception rests upon the assumption that if a surplus of goods or
services exists, they would naturally drop in price to the point where they
would be consumed.
Keynes's theory was significant because it
overturned the mainstream thought of the time and brought about a greater
awareness that problems such as unemployment are not a product of laziness, but
the result of a structural inadequacy in the economic system. He argued that
because there was no guarantee that the goods that individuals produce would be
met with demand, unemployment was a natural consequence. He saw the economy as
unable to maintain itself at full employment and believed that it was necessary
for the government to step in and put under-utilised savings to work through
government spending. Thus, according to Keynesian theory, some individually
rational microeconomic-level actions such as not investing
savings in the goods and services produced by the economy, if taken
collectively by a large proportion of individuals and firms, can lead to
outcomes wherein the economy operates below its potential
output and growth rate.
Prior to Keynes, a situation in which aggregate
demand for goods and services did not meet supply was
referred to by classical economists as a general
glut, although there was disagreement among them as to whether a general
glut was possible. Keynes argued that when a glut occurred, it was the
over-reaction of producers and the laying off of workers that led to a fall in
demand and perpetuated the problem. Keynesians therefore advocate an active
stabilization policy to reduce the amplitude of the business cycle, which they
rank among the most serious of economic problems. According to the theory,
government spending can be used to increase aggregate demand, thus increasing
economic activity, reducing unemployment and deflation.
Theory
Keynes argued that the solution to the Great
Depression was to stimulate the economy ("inducement to
invest") through some combination of two approaches:
- A reduction in interest rates (monetary policy),
and
- Government investment in infrastructure (fiscal
policy).
By reducing the interest rate at which the central
bank lends money to commercial banks, the government sends a signal to
commercial banks that they should do the same for their customers.
Investment by government in infrastructure injects
income into the economy by creating business opportunity, employment and demand
and reversing the effects of the aforementioned imbalance. Governments
source the funding for this expenditure by borrowing funds from the economy
through the issue of government bonds, and because government spending exceeds
the amount of tax income that the government receives, this creates a fiscal
deficit.
A central conclusion of Keynesian economics is
that, in some situations, no strong automatic mechanism moves output and
employment towards full employment levels. This conclusion
conflicts with economic approaches that assume a strong general tendency
towards equilibrium. In the 'neoclassical synthesis', which combines
Keynesian macro concepts with a micro foundation, the conditions of general equilibrium allow for price
adjustment to eventually achieve this goal. More broadly, Keynes saw his theory
as ageneral theory, in which utilization of resources could be high or
low, whereas previous economics focused on the particular case of
full utilization.
The new classical macroeconomics movement,
which began in the late 1960s and early 1970s, criticized Keynesian theories,
while New Keynesian economics has sought to
base Keynes's ideas on more rigorous theoretical foundations.
Some interpretations of Keynes have emphasized his
stress on the international coordination of Keynesian policies, the need for
international economic institutions, and the ways in which economic forces
could lead to war or could promote peace.
Concepts
Wages and spending
During the Great
Depression, the classical theory defined economic collapse as simply a lost
incentive to produce, and the massunemployment as a result of high and rigid real
wages.
To Keynes, the determination of wages is more
complicated. First, he argued that it is not real but nominal wages
that are set in negotiations between employers and workers, as opposed to
a barter relationship. Second, nominal wage
cuts would be difficult to put into effect because of laws and wage contracts.
Even classical economists admitted that these exist; unlike Keynes, they
advocated abolishing minimum wages, unions, and long-term contracts, increasing
labour-market flexibility. However, to Keynes, people will resist nominal wage
reductions, even without unions, until they see other wages falling and a
general fall of prices.
Keynes rejected the idea that cutting wages would
cure recessions. He examined the explanations for this idea and found them all
faulty. He also considered the most likely consequences of cutting wages in
recessions, under various different circumstances. He concluded that such wage
cutting would be more likely to make recessions worse rather than better.
Further, if wages and prices were falling, people
would start to expect them to fall. This could make the economy spiral downward
as those who had money would simply wait as falling prices made it more
valuable—rather than spending. As Irving
Fisher argued in 1933, in his Debt-Deflation Theory of Great
Depressions, deflation (falling prices) can make a
depression deeper as falling prices and wages made pre-existing nominal debts
more valuable in real terms.
Excessive saving
To Keynes, excessive saving, i.e. saving beyond
planned investment, was a serious problem, encouraging recession or
even depression. Excessive saving results if
investment falls, perhaps due to falling consumer demand, over-investment in
earlier years, or pessimistic business expectations, and if saving does not
immediately fall in step, the economy would decline.
The classical economists argued that interest
rates would fall due to the excess supply of "loanable
funds". The first diagram, adapted from the only graph in The
General Theory, shows this process. (For simplicity, other sources of the
demand for or supply of funds are ignored here.) Assume that fixed investment
in capital goods falls from "old I" to "new I"
(step a). Second (step b), the resulting excess of saving causes
interest-rate cuts, abolishing the excess supply: so again we have saving (S)
equal to investment. The interest-rate (i) fall prevents that of production and
employment.
Keynes had a complex argument against this laissez-faire response.
The graph below summarizes his argument, assuming again that fixed investment
falls (step A). First, saving does not fall much as interest rates
fall, since the income and substitution effects of falling rates go
in conflicting directions. Second, since planned fixed
investment in plant and equipment is based mostly on long-term
expectations of future profitability, that spending does not rise much as
interest rates fall. So S and I are drawn as steep
(inelastic) in the graph. Given the inelasticity of both demand and supply,
a largeinterest-rate fall is needed to close the saving/investment gap. As
drawn, this requires a negative interest rate at equilibrium (where
thenew I line would intersect the old S line). However, this
negative interest rate is not necessary to Keynes's argument.
Third, Keynes argued that saving and investment are
not the main determinants of interest rates, especially in the short run.
Instead, the supply of and the demand for the stock
of money determine interest rates in the short run. (This is not
drawn in the graph.) Neither changes quickly in response to excessive saving to
allow fast interest-rate adjustment.
Finally, Keynes suggested that, because of fear of
capital losses on assets besides money, there may be a "liquidity
trap" setting a floor under which interest rates cannot fall. While in
this trap, interest rates are so low that any increase in money supply will
cause bond-holders (fearing rises in interest rates and hence capital losses on
their bonds) to sell their bonds to attain money (liquidity). In the diagram,
the equilibrium suggested by the new I line and the old
S line cannot be reached, so that excess saving persists. Some (such
as Paul
Krugman) see this latter kind of liquidity trap as prevailing in Japan in
the 1990s. Most economists agree that nominal interest rates cannot fall
below zero. However, some economists (particularly those from the Chicago school) reject the existence of
a liquidity trap.
Even if the liquidity trap does not exist, there is
a fourth (perhaps most important) element to Keynes's critique.
Saving involves not spending all of one's income. Thus, it means insufficient
demand for business output, unless it is balanced by other sources of demand,
such as fixed investment. Therefore, excessive saving corresponds to
an unwanted accumulation of inventories, or what classical economists called
a general
glut. This
pile-up of unsold goods and materials encourages businesses to decrease both
production and employment. This in turn lowers people's incomes—and saving,
causing a leftward shift in the S line in the diagram (step B).
For Keynes, the fall in income did most of the job by ending excessive saving
and allowing the loanable funds market to attain equilibrium. Instead of
interest-rate adjustment solving the problem, a recession does
so. Thus in the diagram, the interest-rate change is small.
Whereas the classical economists assumed that the
level of output and income was constant and given at any one time (except for
short-lived deviations), Keynes saw this as the key variable that adjusted to
equate saving and investment.
Finally, a recession undermines the business
incentive to engage in fixed
investment. With falling incomes and demand for products, the desired
demand for factories and equipment (not to mention housing) will fall.
This accelerator effect would shift
the I line to the left again, a change not shown in the diagram
above. This recreates the problem of excessive saving and encourages the
recession to continue.
In sum, to Keynes there is interaction between
excess supplies in different markets, as unemployment in labour markets
encourages excessive saving—and vice-versa. Rather than prices adjusting
to attain equilibrium, the main story is one of quantity adjustmentallowing recessions and
possible attainment of underemployment equilibrium.
Active fiscal policy
As noted, the classicals
wanted to balance the government budget. To Keynes, this would exacerbate the
underlying problem: following either the expansionary policy or the
contractionary policy[clarification needed] would raise
saving (broadly defined) and thus lower the demand for both products and
labour. For example, Keynesians would advise tax cuts instead.
Keynes's ideas influenced Franklin D. Roosevelt's view that
insufficient buying-power caused the Depression. During his presidency,
Roosevelt adopted some aspects of Keynesian economics, especially after 1937,
when, in the depths of the Depression, the United States suffered from
recession yet again following fiscal contraction. But to many the true success
of Keynesian policy can be seen at the onset of World War
II, which provided a kick to the world economy, removed uncertainty, and
forced the rebuilding of destroyed capital. Keynesian ideas became almost
official in social-democratic Europe after the war and in
the U.S. in the 1960s.
Keynes developed a theory which suggested that
active government policy could be effective in managing the economy. Rather
than seeing unbalanced government budgets as wrong, Keynes advocated what has
been called countercyclical fiscal policies, that is,
policies that acted against the tide of the business
cycle: deficit spending when a nation's economy
suffers from recession or when recovery is long-delayed and
unemployment is persistently high—and the suppression of inflation in boom
times by either increasing taxes or cutting back on government outlays. He
argued that governments should solve problems in the short run rather than
waiting for market forces to do it in the long run, because, "in the long
run, we are all dead."
This contrasted with the classical and neoclassical economic analysis of
fiscal policy. Fiscal stimulus could actuate production. But, to these schools,
there was no reason to believe that this stimulation would outrun the
side-effects that "crowd out" private investment: first,
it would increase the demand for labour and raise wages, hurting profitability;
Second, a government deficit increases the stock of government bonds, reducing
their market price and encouraging high interest
rates, making it more expensive for business to financefixed
investment. Thus, efforts to stimulate the economy would be self-defeating.
The Keynesian response is that such fiscal policy
is appropriate only when unemployment is persistently high, above the non-accelerating
inflation rate of unemployment (NAIRU). In that case, crowding out is
minimal. Further, private investment can be "crowded in": Fiscal
stimulus raises the market for business output, raising cash flow and
profitability, spurring business optimism. To Keynes, this accelerator effect meant that government
and business could be complements rather
than substitutes in this situation. Second, as the
stimulus occurs, gross domestic product rises, raising the amount of saving, helping to
finance the increase in fixed investment. Finally, government outlays need not
always be wasteful: government investment in public
goods that will not be provided by profit-seekers will encourage the
private sector's growth. That is, government spending on such things as basic
research, public health, education, and infrastructure could help the long-term
growth of potential output.
In Keynes's theory, there must be significant slack in the labour market before fiscal
expansion is justified.
Contrary to some critical characterizations of it,
Keynesianism does not consist solely of deficit
spending. Keynesianism recommends counter-cyclical policies. An
example of a counter-cyclical policy is raising taxes to cool the economy and
to prevent inflation when there is abundant demand-side growth, and engaging in
deficit spending on labour-intensive infrastructure projects to stimulate
employment and stabilize wages during economic downturns. Classical economics,
on the other hand, argues that one should cuttaxes when there are budget
surpluses, and cut spending—or, less likely, increase taxes—during economic
downturns. Keynesian economists believe that adding to profits and incomes
during boom cycles through tax cuts, and removing income and profits from the
economy through cuts in spending and/or increased taxes during downturns, tends
to exacerbate the negative effects of the business cycle. This effect is
especially pronounced when the government controls a large fraction of the
economy, and is therefore one reason fiscal conservatives advocate a much
smaller government.
Multiplier effect" and interest rates
Main article: Spending multiplier
Two aspects of Keynes's model has implications for
policy:
- First, there is the "Keynesian multiplier", first developed by Richard F. Kahn in 1931. Exogenous increases
in spending, such as an increase in government outlays, increases total
spending by a multiple of that increase. A government could stimulate a great
deal of new production with a modest outlay if: The people who receive this money then spend most
on consumption goods and save the rest.This extra spending allows businesses to hire more
people and pay them, which in turn allows a further increase in consumer
spending. This process continues. At each step, the increase
in spending is smaller than in the previous step, so that the multiplier
process tapers off and allows the attainment of an equilibrium. This story is
modified and moderated if we move beyond a "closed economy" and bring
in the role of taxation: The rise in imports and tax payments at each step
reduces the amount of induced consumer spending and the size of the multiplier
effect.
- Second, Keynes re-analyzed the effect of the
interest rate on investment. In the classical model, the supply of funds
(saving) determines the amount of fixed business investment. That is, under the
classical model, since all savings are placed in banks, and all business
investors in need of borrowed funds go to banks, the amount of savings
determines the amount that is available to invest. Under Keynes's model, the
amount of investment is determined independently by long-term profit
expectations and, to a lesser extent, the interest rate. The latter opens the
possibility of regulating the economy through money
supply changes, via monetary
policy. Under conditions such as the Great
Depression, Keynes argued that this approach would be relatively
ineffective compared to fiscal policy. But, during more "normal"
times, monetary expansion can stimulate the economy.
IS/LM model
The IS/LM model is
nearly as influential as Keynes's original analysis in determining actual
policy and economics education. It relates aggregate demand and employment to
three exogenous quantities,
i.e., the amount of money in circulation, the government budget, and the state
of business expectations. This model was very popular with economists
after World War II because it could be understood in
terms of general equilibrium theory. This
encouraged a much more static vision of macroeconomics than that described
above.
History
Precursors
Keynes's work was part of a long-running debate
within economics over the existence and nature of general
gluts. While a number of the policies Keynes advocated (the notable one
being government deficit spending at times of low private investment or
consumption) and the theoretical ideas he proposed (effective demand, the
multiplier, the paradox of thrift) were advanced by various authors in the 19th
and early 20th centuries, Keynes's unique contribution was to provide
a general theory of these, which proved acceptable to the political
and economic establishments.
Schools
See also: Underconsumption, Birmingham School (economics), and Stockholm school (economics)
An intellectual precursor of Keynesian economics
was underconsumption theory in classical economics, dating from such
19th-century economists as Thomas
Malthus, the Birmingham School of Thomas
Attwood, and
the American economists William Trufant Fosterand Waddill
Catchings, who were influential in the 1920s and 1930s.
Underconsumptionists were, like Keynes after them, concerned with failure
of aggregate demand to attain potential
output, calling this "underconsumption" (focusing on the demand
side), rather than "overproduction" (which would focus on the supply
side), and advocating economic interventionism. Keynes
specifically discussed underconsumption (which he wrote
"under-consumption") in the General Theory, in Chapter
22, Section IV and Chapter
23, Section VII.
Numerous concepts were developed earlier and
independently of Keynes by the Stockholm school during the
1930s; these accomplishments were described in a 1937 article, published in
response to the 1936 General Theory, sharing the Swedish discoveries.
Concepts
The multiplier dates to work in the 1890s
by the Australian economist Alfred De Lissa, the Danish
economist Julius Wulff, and theGerman
American economist Nicholas Johannsen,[16] the
latter being cited in a footnote of Keynes.[17] Nicholas
Johannsen also proposed a theory of effective
demand in the 1890s.
The paradox
of thrift was stated in 1892 by John
M. Robertson in his The Fallacy of Savings, in earlier forms
by mercantilist economists
since the 16th century, and similar sentiments date to antiquity.
Today these ideas, regardless of provenance, are
referred to in academia under the rubric of "Keynesian economics",
due to Keynes's role in consolidating, elaborating, and popularizing them.
Keynes and the classics
Keynes sought to distinguish his theories from and
oppose them to "classical economics," by which he meant the economic
theories ofDavid Ricardo and his followers, including John
Stuart Mill, Alfred Marshall, Francis Ysidro Edgeworth, and Arthur Cecil Pigou. A central tenet of the
classical view, known as Say's law, states that "supply creates its own demand."
Say's Law can be interpreted in two ways. First, the claim that the total value
of output is equal to the sum of income earned in production is a result of a
national income accounting identity, and is therefore indisputable. A second
and stronger claim, however, that the "costs of output are always
covered in the aggregate by the sale-proceeds resulting from demand"
depends on how consumption and saving are linked to production and investment.
In particular, Keynes argued that the second, strong form of Say's Law only
holds if increases in individual savings exactly match an increase in aggregate
investment.
Keynes sought to develop a theory that would
explain determinants of saving, consumption, investment and production. In that
theory, the interaction of aggregate demand and aggregate supply determines the
level of output and employment in the economy.
Because of what he considered the failure of the
“Classical Theory” in the 1930s, Keynes firmly objects to its main
theory—adjustments in prices would automatically make demand tend to the full
employment level.
Neo-classical theory supports that the two main
costs that shift demand and supply are labour and money. Through the
distribution of the monetary policy, demand and supply can be adjusted. If
there were more labour than demand for it, wages would fall until hiring began
again. If there were too much saving, and not enough consumption, then interest
rates would fall until people either cut their savings rate or started
borrowing.
Postwar Keynesianism
Main articles: Neo-Keynesian economics, New Keynesian economics, and Post-Keynesian economics
Keynes's ideas became widely accepted after WWII, and until the
early 1970s, Keynesian economics provided the main inspiration for economic
policy makers in Western industrialized countries. Governments
prepared high quality economic statistics on an ongoing basis and tried to base
their policies on the Keynesian theory that had become the norm. In the early
era of new liberalism and social
democracy, most western capitalist countries enjoyed low, stable
unemployment and modest inflation, an era called the Golden Age of Capitalism.
In terms of policy, the twin tools of post-war
Keynesian economics were fiscal policy and monetary policy. While these are
credited to Keynes, others, such as economic historian David
Colander, argue that they are, rather, due to the interpretation of Keynes
by Abba Lerner in his theory of Functional Finance, and should instead be called
"Lernerian" rather than "Keynesian".
Through the 1950s, moderate degrees of government
demand leading industrial development, and use of fiscal and monetary
counter-cyclical policies continued, and reached a peak in the "go
go" 1960s, where it seemed to many Keynesians that prosperity was now
permanent. In 1971, Republican US President Richard
Nixon even proclaimed "I am now a Keynesian in economics." However,
with the oil shock of 1973, and the economic problems of the 1970s, modern
liberal economics began to fall out of favor. During this time, many economies
experienced high and rising unemployment, coupled with high and rising
inflation, contradicting the Phillips
curve's prediction. This stagflation meant
that the simultaneous application of expansionary (anti-recession) and
contractionary (anti-inflation) policies appeared to be necessary. This dilemma
led to the end of the Keynesian near-consensus of the 1960s, and the rise
throughout the 1970s of ideas based upon more classical analysis,
including monetarism, supply-side economics, and new classical economics. At the same time,
Keynesians began during the period to reorganize their thinking (some becoming
associated with New Keynesian economics); one strategy,
utilized also as a critique of the notably high unemployment and potentially
disappointing GNP growth rates associated with the latter two theories by the
mid-1980s, was to emphasize low unemployment and maximal economic growth at the
cost of somewhat higher inflation (its consequences kept in check by indexing
and other methods, and its overall rate kept lower and steadier by such
potential policies as Martin Weitzman's share economy).
Multiple schools of economic thought that
trace their legacy to Keynes currently exist, the notable ones being Neo-Keynesian economics, New Keynesian economics, and Post-Keynesian economics. Keynes's
biographer Robert Skidelsky writes that the
post-Keynesian school has remained closest to the spirit of Keynes's work in
following his monetary theory and rejecting the neutrality of money.
In the postwar era, Keynesian analysis was combined
with neoclassical economics to produce what is generally termed the "neoclassical synthesis", yielding Neo-Keynesian economics, which
dominated mainstream macroeconomic thought. Though it
was widely held that there was no strong automatic tendency to full employment,
many believed that if government policy were used to ensure it, the economy
would behave as neoclassical theory predicted. This post-war domination by
Neo-Keynesian economics was broken during the stagflation of
the 1970s. There was a lack of consensus among macroeconomists in the 1980s.
However, the advent of New Keynesian economics in the 1990s,
modified and provided microeconomic foundations for the neo-Keynesian theories.
These modified models now dominate mainstream economics.
Post-Keynesian economists, on the other
hand, reject the neoclassical synthesis and, in general, neoclassical economics
applied to the macroeconomy. Post-Keynesian economics is a heterodox school that holds that both Neo-Keynesian
economics and New Keynesian economics are incorrect, and a misinterpretation of
Keynes's ideas. The Post-Keynesian school encompasses a variety of
perspectives, but has been far less influential than the other more mainstream
Keynesian schools.
Relationship
to other schools of economics
The Keynesian schools of economics are situated
alongside a number of other schools that have the same perspectives on what the
economic issues are, but differ on what causes them and how to best resolve
them:
Stockholm School
The Stockholm
School rose to prominence at about the same time that Keynes published
his General Theory and shared a common concern in business cycles and
unemployment. The second generation of Swedish economists also advocated
government intervention through spending during economic downturns although
opinions are divided over whether they conceived the essence of Keynes's theory
before he did.
Monetarism
There was debate between Monetarists and
Keynesians in the 1960s over the role of government in stabilizing the economy.
BothMonetarists and
Keynesians are in agreement over the fact that issues such as business cycles,
unemployment, inflation are caused by inadequate demand, and need to be
addressed, but they had fundamentally different perspectives on the capacity of
the economy to find its own equilibrium and as a consequence the degree of
government intervention that is required to create equilibrium. Keynesians
emphasized the use of discretionary fiscal policy and monetary policy,
while monetarists argued the primacy of monetary policy, and that it should be
rules-based.
The debate was largely resolved in the 1980s. Since
then, economists have largely agreed that central banks should bear the primary
responsibility for stabilizing the economy, and that monetary policy should
largely follow the Taylor rule – which many economists credit with
the Great Moderation. The Global Financial Crisis, however, has
convinced many economists and governments of the need for fiscal interventions
and highlighted the difficulty in stimulating economies through monetary policy
alone during a liquidity trap.
Criticisms
Austrian School criticisms
Austrian economist Friedrich
Hayek criticized Keynesian economic policies for what he called their
fundamentally "collectivist" approach, arguing that such theories
encourage centralized planning, which leads to malinvestment of capital, which
is the cause ofbusiness cycles. Hayek also argued
that Keynes's study of the aggregate relations in an economy is fallacious, as
recessions are caused by micro-economic factors. Hayek claimed that what starts
as temporary governmental fixes usually become permanent and expanding
government programs, which stifle the private sector and civil society.
Austrian economist Henry
Hazlitt criticized, paragraph by paragraph, Keynes's General Theory in The Failure of the New Economics.
New Classical Macroeconomics criticisms
See also: Lucas
critique
Another influential school of thought was based on
the Lucas critique of Keynesian economics. This
called for greater consistency withmicroeconomic theory
and rationality, and in particular emphasized the idea of rational expectations. Lucas and others
argued that Keynesian economics required remarkably foolish and short-sighted
behavior from people, which totally contradicted the economic understanding of
their behavior at a micro level. New classical economics introduced a
set of macroeconomic theories that were based on optimising microeconomic behavior.
These models have been developed into the Real Business Cycle Theory, which argues
that business cycle fluctuations can to a large extent be accounted for by real
(in contrast to nominal) shocks.
Beginning in the late 1950s new classical
macroeconomists began to disagree with the methodology employed by Keynes and
his successors. Keynesians emphasized the dependence of consumption on
disposable income and, also, of investment on current profits and current cash
flow. In addition, Keynesians posited a Phillips
curve that tied nominal wage inflation to unemployment rate. To
support these theories, Keynesians typically traced the logical foundations of
their model (using introspection) and supported their assumptions with
statistical evidence. New
classical theorists demanded that macroeconomics be grounded on the same
foundations as microeconomic theory, profit-maximizing firms and rational,
utility-maximizing consumers.
The result of this shift in methodology produced
several important divergences from Keynesian Macroeconomics:
- Independence of Consumption and current Income
(life-cycle permanent income hypothesis)
- Irrelevance of Current Profits to Investment (Modigliani-Miller theorem)
- Long run independence of inflation and unemployment
(natural rate of unemployment)
- The inability of monetary policy to stabilize
output (rational expectations)
- Irrelevance of Taxes and Budget Deficits to
Consumption (Ricardian Equivalence)
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