Krugman is “transitioning to the left” only so far as to recognize the
obvious stagnant real wages and declining wage share of income in the US in
recent years and to worry about the “uncomfortable” implications of these
facts.  But his *explanation* of these facts is in terms of the widely
criticized marginal productivity theory of distribution, according to which
profit is determined by the “marginal product of capital” (as opposed to
the surplus labor of workers).  His explanation of stagnant real wages is
“capital-biased technological change”, which is defined as technological
change which increases the “marginal product of capital” in relation to the
“marginal product of labor” (i.e. ↑MPK/MPL).  This is such BS! Marginal
products do not exist and can’t explain anything.



Below is a response of mine to another recent post by Krugman on the same
subject.  It also refers to a prior post by Krugman and a prior criticism
by me which was posted on the Economist’s View blog.



I would appreciate comments.



Fred





*Krugman’s explanation of stagnant real wages*


This is a brief response to a recent post by Paul Krugman on his blog about
“capital-biased technological change” as an explanation of stagnant real
wages and the declining wage share of income:  (
http://krugman.blogs.nytimes.com/2012/12/26/capital-biased-technological-progress-an-example-wonkish/
).
This is a follow-up to a previous comment of mine on Economists’ View:
http://economistsview.typepad.com/economistsview/2012/12/krugmans-explanation-of-stagnant-real-wages.html

which was a response to a previous post on this subject by Krugman:

http://krugman.blogs.nytimes.com/2012/12/10/technology-and-wages-the-analytics-wonkish
)



Krugman still has not clearly defined what he means by “capital-biased
technological change”, but he says that he is following Hicks (1932), and
Hicks definition is technological change which increases the marginal
product of capital (MPK) more than the marginal production of labor (MPL);
i.e. ↑MPK > ↑MPL (at a given K/L ratio).  Thus, Krugman’s definition of
“capital-biased technological change” is in terms of the *marginal products
*of the marginal productivity theory of distribution.



Krugman presents an example of office work with two inputs (capital and
labor) and two possible techniques, one capital-intensive and one
labor-intensive.  However, this example does not include raw materials (and
other intermediate inputs), and thus does not address the criticism that *raw
materials render the concept of the MPL (or the MPK) impossible *(a
criticism which I made in my earlier post and which goes back to Hobson and
Pareto in the early 20th century).  Raw materials cannot be held constant
(as the concept of marginal product of labor or capital requires) while
increasing labor (or capital) and output.  In order to produce another car,
one must have additional wheels, brakes, etc.  And between labor and raw
materials, there is *only one factor proportion possible *(i.e. only one
“technique”), so Krugman’s example of two techniques and extrapolation to a
“bunch” of techniques (the usual hand-waving to approach a “smooth
isoquant”) does not apply.  There is *no isoquant *(kinked or smooth)
between labor and raw materials.  One cannot increase labor and reduce raw
materials and produce the same quantity of output.  A car still needs four
wheels.



In order to reassure readers with doubts about marginal productivity theory
(“if you’re worried”), Krugman just asserts that “labor and machines are
paid their marginal products”.  I argue that this conclusion is invalid in
cases that include raw materials, since marginal products *do not exist *in
these cases.



I agree with Krugman that technological change is replacing labor, not just
low-skilled labor, but also medium-skilled labor, and even increasingly
high-skilled labor (as he has been writing about:
http://krugman.blogs.nytimes.com/2012/12/08/rise-of-the-robots/)

But this important phenomenon cannot be analyzed in terms of MPK and MPL
because these marginal products do not exist.



There are a number of other major (and probably insoluble) problems with
marginal productivity theory that are fairly well known and have been known
for a long time:  the “aggregation” problem, the “adding-up” problem, the
“reswitching” problem, the “multi-causality” problem (which is similar to
the “raw materials” problem in that it renders marginal products
impossible), the precise definition of the “price of capital”, the lack of
adequate theories of the supply of either labor or capital, etc..  But the
impossibility of marginal products in production processes that include raw
materials is the most obvious insoluble problem.



Marx’s theory predicted in the early days of capitalism that technological
change would tend to be labor-saving (in the usual sense of using less
labor to produce the same quantity of output, not in Hicks’ and Krugman’s
sense of a ratio of marginal products), and this labor-saving technological
change would cause increasing unemployment (the “reserve army of the
unemployed”) which in turn would put downward pressure on wages and the
wage share of income (*Capital*, Volume 1, Chapter 25).  He called this
important conclusion “The General Law of Capital Accumulation” (the title
of Chapter 25).  One does not have to use the very dubious marginal
productivity theory to explain these important phenomena.  Marx’s theory
provides a perfectly adequate explanation without the extremely problematic
concepts of marginal products of labor and capital.



To his credit, Krugman acknowledges in another recent post
http://krugman.blogs.nytimes.com/2012/12/08/rise-of-the-robots/

that the current capital-labor dimension of inequality “has echoes of
old-fashioned Marxism – which shouldn’t be reason to ignore the facts, but
too often it is.”  But Krugman still wants to explain these “uncomfortable”
facts in terms of marginal products and marginal productivity theory, in
spite of the many well-known deficiencies of this theory.  I suggest that
he should not ignore, not only these facts, but also Marx’s robust *theoretical
explanation *of these facts and the capital-labor dimension of inequality.



Fred Moseley



On Wed, Jan 2, 2013 at 10:07 AM, c b <[email protected]> wrote:

> Re: [Pen-l]
> Ann Davis(nib)
>
> Now maybe the left can pay some attention to technological
> change....which has been out of style among Marxists since the
> 1970s....alas.
>
>
>
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