Re: What is emergence?

[Russell Standish]

Rayman Mohamed wrote:
> 
> 
> My question would be whether the following will qualify as 
> emergence.  Consider developers looking for sites on which to build 
> houses.  Developers have rules of behavior that lead them to certain 
> sites.  However, the spatial pattern that emerges is not merely as a result 
> of developer behavior, but rather of the characteristics of the search 
> space.  For example, soil types that are suitable for septic systems make 
> certain sites desirable over others.  Or a network of roads may already 
> exist which again make some sites preferable to others.  In both cases, the 
> developer spends less money and so increases profits.
> 
> The rule that a developer follows is simple -- maximize profits.  However, 
> this rule micro rule is related to the search space which directs 
> developers to certain cites.  (In the absence of these site 
> characteristics, the only reason for developers to build next to each other 
> might be because the profit function contains a variable that reflects how 
> much nearby development exists.  Nearby development indicates that other 
> developers have tried this area before and have found it to be successful, 
> or something like that.)
> 
> So my question is: Does the presence of site characteristics which direct 
> developers to certain sites mean that the pattern that results cannot be 
> described as emergent?
> 
> Thanks for your insights,
> 
> 
> 
> Rayman
> 
> 
> 

If the pattern of development was completely determined by the local
characteristics of the site, then no, you don't have emergence. For
example, the shape of waterways is determined completely by elevation
of land. One wouldn't describe the shape of waterways to be emergent
with respect to the elevation of land.

However, in you model, presumably interaction between agents also
affects the pattern of development (eg you'd want to site your houses
near schools and shops - and you'd want to site your schools and shops
near concentrations of houses). Even though geography may influence
the dyanamics, it by no means determines it, so you'd still have an
emergent system.

                                                Cheers

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Dr. Russell Standish                     Director
High Performance Computing Support Unit, Phone 9385 6967                    
UNSW SYDNEY 2052                         Fax   9385 6965                    
Australia                                address@hidden             
Room 2075, Red Centre                    http://parallel.hpc.unsw.edu.au/rks
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