[FRIAM] FRIAM and causality

[Glen E. P. Ropella]

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Marcus G. Daniels on 12/08/2007 09:24 AM:
> For a fixed instruction set there's a fixed set of programs that can be 
> encoded in a fixed sized vector.   The behaviors that such a program can 
> exhibit are also entirely fixed given precise initial state.

Unfortunately, most models are not built atop fixed instruction sets.
Most models are built atop a very complicated stack of abstraction
layers, which means the effective number of "instructions" and terminals
(data types as well as values) is infinite.  If we were building our
models in, say, assembly, I might agree with you.

> General 
> and effective methods for global search can in fact be exactly the same 
> for numbers and rules:   0) create a set of starting candidates 1) 
> evaluate them, 2) tweak the good 3) destroy the bad, 4) go to 1.

You're playing language games.  Yes, the methods _can_ be the same in
the extreme case you lay out.  But, in fact they are NOT the same in
most cases.

> For that matter [-10, 100] is not a well 
> defined space for a model because there are no units, and no given 
> meaning to how that range ought to relate to sensitivities in other agents.

It is a well-defined space, regardless of its lack of context.  Adding
more information helps make the search more effective.  But, the fact
that it's a regular set of ordered values with defined boundaries makes
it an easy space to search.  So, in the absence of contextual
information, it is still easy to define an algorithm to search it.

> An agent model is an assembly.  If a component of the assembly is 
> tweaked a bit, that doesn't justify calling it a whole new model any 
> more than if a few parameters in the model changed a bit.   It is a 
> versioning issue.

This is a sweeping and unjustified generalization.  For example, most OO
based models are not changed by changing a single component of the
model.  In most OO based models, one makes changes to an entire _class_
of components.  And in that sense, it is only a versioning issue for the
source code that generates the model.  It is NOT a versioning issue for
the dynamic execution of the model.  It is an issue of design of
experiments.  The source code is not the model, it's merely one of the
many generators for the model.

- --
glen e. p. ropella, 971-219-3846, http://tempusdictum.com
To read a newspaper is to refrain from reading something worthwhile. The
first discipline of education must therefore be to refuse resolutely to
feed the mind with canned chatter. -- Aleister Crowley

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