Re: A whiff of reality...

[Gary Polhill]

Doug Donalson wrote:
> 
> Here is a reference I ran across when writing the final chapter of my
> dissertation.
> 
> Rykiel, E.J., 1996. Testing ecological models: the meaning of validation.
> Ecol. Model. 90, 229-244.
> 
> Although the it is about "validation", at least it's a whack at applying a
> structure to one of these problems.  I have had several (actually, many more
> than several) arguments with my advisor and other committee members about
> including "verification" procedures in at least in a paper appendix.  The
> general feeling is that this would be like experimentalists including
> details of instrument calibration procedures.  (Ecologists make Joe Friday
> look like a light weight with "Just the facts, ma'am".  Nothing but that
> which is essential for the development of the idea in the paper should be
> included, and model testing, at this point is considered a distraction.)  I
> personally don't agree until we have verification methods as well
> delinieated as those for experimental instruments.  (Of course, in all
> cases, you still have to apply the methods.)
> 
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

Gary

-- 

Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen. AB15 8QH
Tel: +44 (0) 1224 318611               Email: address@hidden


                  ==================================
   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.
                  ==================================