Re: A whiff of reality...

[glen e. p. ropella]

At 01:40 PM 5/3/00 +0100, you wrote:
> I think maybe the problem is that it is always possible to have a model
> that predicts the observables, but is not a "true" representation of
> what is going on in reality... A bit like the Ptolemy/Copernicus models
> of the solar system Cal mentioned earlier.
>
> Or maybe the real problem is not imperfect models but imperfect
> observations....?

Right on both counts.


> >
> > It's immanently clear that many people don't understand two
> > things about validation and verification: 1) that they are
> > inextricably tied up in the observables (Smith, Popper, Maturana, etc.)
> > and 2) that they differ only in the subjective ontological status
> > of their referents (i.e. system A is "reality" whereas system B is
> > "a computer program... the only difference between "reality" and a
> > "computer program" lies in the scientists mind.)
>
> Not sure about point 2. Isn't the whole point of building a model
> to give you some kind of predictive/explanatory power in reality?
> After all, you are not trying to establish the validity of reality
> against your model (unless, perhaps, you are an economist ;-) ...).
> OK OK, so maybe from the point of view of validation there is no
> difference -- you've just got two sets of data, but (and call me
> an egoist), I think the difference between their origins (though it
> is only in my mind) is important.

Not at all!  The point of building a model is not to give predictive
power in reality.  The point is to give explanatory power and provide
a pathway to *estimation*.  In some cases, estimation is seen as a
kind of weak prediction, and it's referred to as "prediction".  But,
it's not, really.  Estimation is the discipline of finding telemetry
points, applying instrumentation, taking measurements, and fitting
those measurements with a model.  (Control picks up from there and
attempts to use the estimation to force the system.)

We engage in the exact same operational process when estimating
a physical/biological system as we do when estimating a computer
program.  So, the map of "validation" just like the map of
"verification" is bijective.  Validating a model to reality is
the same as validating reality to a model.

There have been all sorts of silly attempts to express why we
tend to be anthrocentric in our understanding of the world.
(e.g. why we believe we're conscious but lower animals, machines,
or objects aren't).  My advice to those of us that think there
is a real objective distinction between one system and another
is to keep that little secret delusion to ourselves and pretend
it doesn't exist.  [grin]  Leave it to philosophers and theologians.

glen

--
glen e. p. ropella =><= The front line is everywhere. Hail Eris!
Home: http://forager.swarm.com/~gepr             (505) 424-0448
Work: http://www.swarm.com                       (505) 995-0818


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