The phrase "the simulation" has been used frequently in this
long thread, so we may wish to better define it first, and relate it to
"model", specifically.

What is meant to social modelers by the phrase "the simulation"?
To those within the simulation community (i.e., focusing on
the discipline rather than on a specific application), "simulation"
refers to a numerical solution for a model, usually in one of
three forms (discrete event, continuous, or hybrid/combined) although others
certainly exist (parallel and distributed simulation). However, "simulation"
can also refer more broadly to the field itself, where one performs
"the process of simulation": building models from theories, executing
the models (i.e., simulating them), and validating the model output
against observation.

Getting back to the thread, this begs the question of how explanation
fits into all of this. The model can be a source for explanation,
and so can the simulation (or analytic solution if possible) of the 
model. 

-paul

Paul Fishwick, PhD
Professor, University of Florida
http://www.cise.ufl.edu/~fishwick
Email: [log in to unmask]
 

=>  -----Original Message-----
=>  From: News and discussion about computer simulation in the social
=>  sciences [mailto:[log in to unmask]] On Behalf Of Christopher J.
=>  Mackie
=>  Sent: Friday, November 14, 2003 9:50 AM
=>  To: [log in to unmask]
=>  Subject: Re: Simulation and explanation
=>  
=>  I'd like to follow up Kathleen Carley's point about the theory being the
=>  simulation.  In addition to the AI/DAI literature, there is a developed
=>  position in the philosophy of science based in part around the idea that
=>  the model is the theory (I'm grossly simplifying a very sophisticated
=>  argument).   It's an anti-Realist school of thought called Constructive
=>  Empiricism, and I've long suspected that it makes a more sensible
=>  philosophical foundation for the kinds of questions social modelers tend
=>  to like to ask than do the Realist accounts that most of us feel obliged
=>  to deploy.  One of the most formative works in that tradition is Bas van
=>  Fraasen's _The Scientific Image_ (Oxford 1980: ISBN 0198244274), which
=>  won the Matchette Prize and the Lakatos Award back when it came out.
=>  His most recent work in this same vein is _The Empirical Stance_ (Yale
=>  2002: ISBN 0300088744), which will catch you up on the 20 years of point
=>  and counterpoint that followed.  Both are worth a careful read if you
=>  enjoy this sort of thing (you might want to read in reverse order, as
=>  the later book was written for a more general audience).  Van Fraasen's
=>  web site collects some useful reviews of _The Empirical Stance_ by Paul
=>  Thagard, Richard Rorty, and others:
=>  http://webware.princeton.edu/vanfraas/pubs/index.htm
=>  
=>  I'm also curious about an issue that seems to me to be lurking within
=>  this conversational thread.  How should we understand the concepts of
=>  necessary and sufficient conditions in the context of emergence and
=>  social complexity?  Do they become more valuable or less, when we're
=>  seeking to understand non-linear, highly contextual influences on social
=>  phenomena?  Is 'necessary and sufficient' really necessary and
=>  sufficient to construct causal accounts of emergence, or do we need to
=>  modify our understandings in order to make meaningful claims about
=>  causation in the presence of complexity?
=>  
=>  --Chris Mackie
=>  PhD Candidate, Woodrow Wilson School,
=>  Princeton University