Re: A whiff of reality...

[glen e. p. ropella]

At 06:26 PM 5/2/00 +0100, you wrote:
> Just to add my tuppence-ha'penny's worth (English for two cents), there is
> an interesting paper about validation and verification by Naomi Oreskes and
> others in Science vol.263 (1994) pp 641-646. They argue that except in a
> closed system, validation of models is not possible, since you are committing
> the logical fallacy of affirming the consequent:
>
> Assume: If any model is valid, then it will predict the data
> Assume: My model predicts the data
> Conclude: My model is valid

This seems pretty odd to me.  Validation consists of:
1. taking data off of two systems
2. comparing and contrasting the two data sets
3. quantifying the degree to which the two data sets are different

The "my model is valid" decision lies inextricably in the
observables and the tolerances for sameness and difference.

The only condition under which "validation is impossible" is
when there aren't two systems that can be measured.  Even if
one system is measured in a completely different way or with
completely different mechanisms, one can always deductively
transform the data taken from one system into something
roughly commensurate with that taken from the other system.
So, as long as one can take data from the two systems, the
exercise of validation can be done.  Granted, obviously, the
proof of validity (especially in a deductive sense) is often
impossible because the observables usually contain less information
than the system, itself, contains.  So, one cannot preserve
the validity of a deduction from the system by deducing from the
observables.

Hence the desire to use formally grounded systems.  But, in
science (by which, of course, I mean natural science [grin])
it's not even clear what the formal grounding for the extant
system is, so all we have to derive from are our observables
(and certain well justified inferred laws).

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.)

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


                 ==================================
  Swarm-Modelling is for discussion of Simulation and Modelling techniques
  esp. using Swarm.  For list administration needs (esp. [un]subscribing),
  please send a message to <address@hidden> with "help" in the
  body of the message.
                 ==================================