克鲁格曼解释为什么奥地利学派的产能过剩论是有害的
2015-05-03 12:43阅读：
The Hangover Theory
Are recessions the inevitable payback
for good times?
By Paul Krugman 12.
1998
A few weeks ago, a journalist
devoted a substantial part of
a profile of yours truly
to my failure to pay due
attention to the 'Austrian
theory' of the business cycle—a
theory that I regard as
being about as worthy of
serious study as the phlogiston
theory of fire. Oh well.
But the incident set me
thinking—not so much about that
particular theory as about the
general worldview behind it.
Call it the overinvestment
theory of rece
ssions, or 'liquidationism,' or just
call it the 'hangover theory.'
It is the idea that
slumps are the price we
pay for booms, that the
suffering the economy experiences
during a recession is a
necessary punishment for the
excesses of the previous
expansion.
The hangover theory is perversely
seductive—not because it offers
an easy way out, but
because it doesn't. It turns
the wiggles on our charts
into a morality play, a
tale of hubris and downfall.
And it offers adherents the
special pleasure of dispensing
painful advice with a clear
conscience, secure in the belief
that they are not heartless
but merely practicing tough
love.
Powerful as these seductions may
be, they must be resisted—for
the hangover theory is
disastrously wrongheaded. Recessions
are not necessary consequences
of booms. They can and
should be fought, not with
austerity but with liberality—with
policies that encourage people
to spend more, not less.
Nor is this merely an
academic argument: The hangover
theory can do real harm.
Liquidationist views played an
important role in the spread
of the Great Depression—with
Austrian theorists such as
Friedrich von Hayek and Joseph
Schumpeter strenuously arguing, in
the very depths of that
depression, against any attempt
to restore 'sham' prosperity by
expanding credit and the money
supply. And these same views
are doing their bit to
inhibit recovery in the world's
depressed economies at this very
moment.
The many variants of the
hangover theory all go something
like this: In the beginning,
an investment boom gets out
of hand. Maybe excessive money
creation or reckless bank
lending drives it, maybe it
is simply a matter of
irrational exuberance on the
part of entrepreneurs. Whatever
the reason, all that investment
leads to the creation of
too much capacity—of factories
that cannot find markets, of
office buildings that cannot
find tenants. Since construction
projects take time to complete,
however, the boom can proceed
for a while before its
unsoundness becomes apparent.
Eventually, however, reality
strikes—investors go bust and
investment spending collapses. The
result is a slump whose
depth is in proportion to
the previous excesses. Moreover,
that slump is part of the
necessary healing process: The
excess capacity gets worked off,
prices and wages fall from
their excessive boom levels, and
only then is the economy
ready to recover.
Except for that last bit about
the virtues of recessions, this
is not a bad story about
investment cycles. Anyone who
has watched the ups and
downs of, say, Boston's real
estate market over the past
20 years can tell you
that episodes in which
overoptimism and overbuilding are
followed by a bleary-eyed
morning after are very much
a part of real life. But
let's ask a seemingly silly
question: Why should the ups
and downs of investment demand
lead to ups and downs in
the economy as a whole?
Don't say that it's
obvious—although investment cycles
clearly are associated with
economywide recessions and recoveries
in practice, a theory is
supposed to explain observed
correlations, not just assume
them. And in fact the key
to the Keynesian revolution in
economic thought—a revolution that
made hangover theory in general
and Austrian theory in
particular as obsolete as
epicycles—was John Maynard Keynes'
realization that the crucial
question was not why investment
demand sometimes declines, but
why such declines cause the
whole economy to slump.
Here's the problem: As a matter
of simple arithmetic, total
spending in the economy is
necessarily equal to total
income (every sale is also
a purchase, and vice versa).
So if people decide to
spend less on investment goods,
doesn't that mean that they
must be deciding to spend
more on consumption goods—implying
that an investment slump should
always be accompanied by a
corresponding consumption boom? And
if so why should there be
a rise in unemployment?
Most modern hangover theorists probably
don't even realize this is
a problem for their story.
Nor did those supposedly deep
Austrian theorists answer the
riddle. The best that von
Hayek or Schumpeter could come
up with was the vague
suggestion that unemployment was
a frictional problem created as
the economy transferred workers
from a bloated investment goods
sector back to the production
of consumer goods. (Hence their
opposition to any attempt to
increase demand: This would
leave 'part of the work
of depression undone,' since
mass unemployment was part of
the process of 'adapting the
structure of production.') But
in that case, why doesn't
the investment boom—which presumably
requires a transfer of workers
in the opposite direction—also
generate mass unemployment? And
anyway, this story bears little
resemblance to what actually
happens in a recession, when
every industry—not just the
investment sector—normally contracts.
As is so often the case
in economics (or for that
matter in any intellectual
endeavor), the explanation of
how recessions can happen,
though arrived at only after
an epic intellectual journey,
turns out to be extremely
simple. A recession happens
when, for whatever reason, a
large part of the private
sector tries to increase its
cash reserves at the same
time. Yet, for all its
simplicity, the insight that a
slump is about an excess
demand for money makes nonsense
of the whole hangover theory.
For if the problem is
that collectively people want to
hold more money than there
is in circulation, why not
simply increase the supply of
money? You may tell me
that it's not that simple,
that during the previous boom
businessmen made bad investments
and banks made bad loans.
Well, fine. Junk the bad
investments and write off the
bad loans. Why should this
require that perfectly good
productive capacity be left
idle?
The hangover theory, then, turns
out to be intellectually
incoherent; nobody has managed
to explain why bad investments
in the past require the
unemployment of good workers in
the present. Yet the theory
has powerful emotional appeal.
Usually that appeal is strongest
for conservatives, who can't
stand the thought that positive
action by governments (let
alone—horrors!—printing money) can ever
be a good idea. Some
libertarians extol the Austrian
theory, not because they have
really thought that theory
through, but because they feel
the need for some prestigious
alternative to the perceived
statist implications of Keynesianism.
And some people probably are
attracted to Austrianism because
they imagine that it devalues
the intellectual pretensions of
economics professors. But moderates
and liberals are not immune
to the theory's seductive
charms—especially when it gives
them a chance to lecture
others on their failings.
Few Western commentators have resisted
the temptation to turn Asia's
economic woes into an occasion
for moralizing on the region's
past sins. How many articles
have you read blaming Japan's
current malaise on the excesses
of the 'bubble economy' of
the 1980s—even though that
bubble burst almost a decade
ago? How many editorials have
you seen warning that credit
expansion in Korea or Malaysia
is a terrible idea, because
after all it was excessive
credit expansion that created
the problem in the first
place?
And the Asians—the Japanese in
particular—take such strictures
seriously. One often hears that
Japan is adrift because its
politicians refuse to make hard
choices, to take on vested
interests. The truth is that
the Japanese have been
remarkably willing to make hard
choices, such as raising taxes
sharply in 1997. Indeed, they
are in trouble partly because
they insist on making hard
choices, when what the economy
really needs is to take
the easy way out. The
Great Depression happened largely
because policy-makers imagined that
austerity was the way to
fight a recession; the
not-so-great depression that has
enveloped much of Asia has
been worsened by the same
instinct. Keynes had it right:
Often, if not always, 'it
is ideas, not vested interests,
that are dangerous for good
or evil.
◆◆

