Re: Heterodoxers are crackpots

["John M. Legge" <jlegge@xxxxxxxxxxxxxx>]

Bruce,

you have lost the point.

Non-ergodicity can arise in a fully deterministic system simply by linking
events; this is why the geometric random walk is one of the simplest
nonergodic processes. By the 1930s if not earlier economists had recognised
that systems did not have to be very complicated before they lost the
ergodic property and entered on a formally unpredictable path.  The motion
of the earth and moon around the sun is nonergodic: unless an astronomer had
access to infinitely precise measurements of the state of the solar system
at an instant of time, and an infinitely powerful computer with which to
process this information, she could not make reliable predictions of such
ordinary events as an eclipse of the sun for more than ten thousand or so
years into the future.

Human society is more complex, and your example of an entrepreneur trying to
predict demand for a yet-uninvented product fifteen years into the future is
probably on a par with an astronomer talking about eclipses a million years
or from now; but in my view there is no fundamental difference:
unpredictability is a fundamental property of the universe.  There is no
need to invent a source of fundamental uncertainty into a system in which
fundamental unpredictability is already present.

More dangerously, in my view, adding an axiom of uncertainty denies the
assumption of causality on which science relies.  If PKers choose to rely on
an axiom of uncertainty I do not know how they/we can challenge those of the
orthodox school who assert fundamental ergodicity.  They implicitly rely on
a God who coordinates individual choices to as to make intrinsically
nonergodic outcomes obey ergodic laws; but PKers are asked to call upon a
different God to play dice with the laws of the universe and thereby produce
uncertainty in circumstances where unpredictability would have preserved the
laws of physics and still been a sufficient condition to support every
conclusion of PK analysis,

JML


> -----Original Message-----
> From: pkt-owner@xxxxxxxxxxxxxxxx [mailto:pkt-owner@xxxxxxxxxxxxxxxx]On
> Behalf Of Bruce McFarling
>  At 12:00 PM 9/1/02 +1000, John M. Legge wrote:
> >
> >For an event to be truly uncertain it would have to be
> unpredictable a
> >picosecond before it occurred to an observer a nanometre
> away from it.
>
> Again, there is no way that such a statement can be an *argument*, it
> is simply a *definition* of a particular use of the phrase.  There is
> nothing in this definition that is of much interest to the following
> position in the current intellectual discourse about economics:
>
>