Re: Occam's Razor

[pdavidso <pdavidso@xxxxxxx>]

>===== Original Message From Gunnar Tomasson <gunnar.tomasson@xxxxxxxxxxx>
=====
>
>I submit that my following proposition accords with Hilbert's point A:
>
>> >If, as I suggest, axiomatic structures become Theorems X, Y, and Z are
>> >"non-overlapping" in the sense that the rules/games of (a) Chess, (b)
>> >Contract Bridge, and (c) Gin Rummy may be said to be so, then the number
>of
>> >axioms is immaterial.

There are no rules (axioms that are common to Chess and to Bridge -- so I do
not see the relevance of your comments.
>
>You comment on my proposition as follows:
>
>> I am sorry to say but these comments below are irrelevant. If Theories X,
>Y,
>> and Z do not share any common axioms then your point is correct --BUT
>> our discussion requires the recognition that all economic theories share
>some
>> common axiooms. It is not that on the first Monday economics is a game of
>> bridge, on Tuesdays it is a game of gin rummy; on wednesday -- blackjack,
>etc,
>> Or ar you arguing that the rules of the economicgame change every day?
>
>I disagree - Hilbert's point A applies to (X) Newton's Gravitational Model;
>(Y) Einstein's Gravitational Model/General Relativity; and (Z) any would-be
>Quantum Mechanical Model of Gravity all of which "share" or have in "common"
>the "field" axiom.
>

Notice you have three models all oabout gravity.  Einstein's called his theory
the GENERAL theory of relativity because it required less axioms than
Newton's.

Moreover, bioth Lord Robert Skidelsky (Keynes's biograpgher) and Jamie
Galbraith a have written that it is not accidental that the first three words
in the title of Keynes's 1936 book mimics Einstein's first three words in his
monumental work -- for both of them were able to explain more things in there
theory by invoking fewer restrictive axioms.  If you do not belikeve this you
should read Keynes's preface to the German language edition of the General
Theory -- where Keynes specifically says that he calls his theory general as
compared to the classical thoery because it requires "fewer restrictive
axioms". [ Please note that you must read the German langauge edition to see
his quote -- not the english translation of the German edition's preface in
CWK.



>I also submit that my following suggestion accords with Hilbert's point B:
>
> > >Indeed, as indicated by Einstein's comments on the General Theory's
>"logical
>> >completeness," remove one axiom and the whole axiomatic structure
>("theory")
>> >reduces to incoherence.

Because Einstein's General Theory contains fewer axioms -- if it is the most
general theory conceivable then it is true that removing one axiom from its
foundation reduces it to incoherence!!


>
>You comment as follows:
>
>> Not necessarily as my example of he classical fixity of money wages
>implies--
>> IF one removes the fixity assumption, the ergodic axiom [so that
>uncertainty
>> is the motivating force behind a demand for liquidity] and the lack of
>gross
>> substituion (only) between liquid assets and illiquid products of
>industry --
>> while stil permitting gross sunstition among the products of industry --
>and
>> one has a comlete system (with fewer restrictive axioms) showing the truth
>of
>> the possibility of involuntary unemployent. The resulting complete logical
>> system known as THE GENERAL THEORY OF EMPLOYMENT INTEREST AND MONEY
>
>In response, I submit that Keynes' modus operandi represented "a practice
>which in the rigorously logical building up of a theory is not admissible."

Clearly here we differ and communication breaks down between us.  Bu8t I note
you do not deny that Keynes's analysis requires fewer restrictive axioms than
the classical [neoclassical] theory -- so casting stones of "not admissible"
is not relevant IMHO.

Paul

Paul Davidson
Editor, Journal of Post Keynesian Economics
University of Tennessee
SMC 503
Knoxville, Tennessee 37996-0550
phone # (561)369-1951; fax #(561)369-1951;
email pdavidson@xxxxxxx
http://econ.bus.utk.edu/davidsonextra/Davidson.html