Re: What is emergence?

[Russell Standish]

address@hidden wrote:
> For example in the macroeconomic language there is the well known 
> concept of "recession". The first time we *observe* recession we
> *discover* it, recognize a *pattern* (occupation, inflation, etc.) and
> name this pattern *recession*, adding a new term to the macro language
> *not conteined* before.
> Now there are a lot of efforts in studying "how recession emerges", 
> but any time we percive recession (observe the defined pattern), 
> we say that a new recession has emerged without adding nothing new
> to our macrolanguage.
> 
> It is for this reason that I prefer to link the concept of emergence
> to the observation of a pattern in a macro and micro world, each one
> defined by the appropriate language.
> 

I think we're in good agreement here.

> 
> With regard to the emergence at the microlevel (if definable), may be
> I haven't choose the right examples. Now I will try with another one, 
> may be it is not as broadly known as water and social behavior, but I
> think it is quite common and easy to understand for thouse new to it.
> This exaple is the study of the prisoners dilemma made by R. Axelrod
> using genetic algorithms ("The evolution of strategies in the iterated
> prisoner's dilemma" R. Axelrod, Genetic algorithms and simulated 
> annealing ed. Lawrence Davis 1987, 32-41; you can find it in the book
> "The complexity of cooperation: agent based models of competition and 
> collaboration" R. Axelrod, Princeton 1997, ISBN:0-691-01567-8).
> 
> In this study any agent have its behavior coded in a gene: simply a 
> vector where the index of the vector indicates the previos history
> of the game, and the vector contains the next action to do given
> the past history (Cooperate or Defect). So we can think of the gene
> as a vector of C and D.
> So the micro language describe the vector, how the agents interacts, and 
> what happends if they cooperate or not (given agent a and b there are
> payoffs defined for ab = CC, CD, DC, DD).
> The micro language describe what is the vector and what does it means, 
> the language cannot define where in the vector must be C or D, couse
> it is the object of the experiment.
> At the macro level the language define the mean score of the group
> of agents (20 agents in the expriment).
> 
> Running the experiment the observer can see at the macro level that
> the avarage score falls down (so defection emerges), and than rise up
> ( cooperation emerges, more precisely reciprocation).
> But defection and cooperation are something defined within
> the microlanguage as particular patterns of the gene.
> 

This is an example of "simple emergence", whereas the entropy and
recession examples are "complex emergence". I'm not sure who
introduced these terms, but a number of authors have drawn this
distinction. Cohen and Stewart introduce the terms "simplicity and
complicity" to describe this distinction in "Collapse of Chaos". In
the example of the ideal gas, temperature and pressure are simply
emergent, as they are simply averages of some quantity present in the
microscopic description. Entropy is complexly (complicitly?) emergent,
because its definition requires extra information decided upon by some
observer.

If what "simple emergence" is what you mean by "emergence in the
micorscopic level", then sure that exists.


> This bring us to another question:
> Is emergence a state or a process ?
> I think it is a process.
> 

I don't really think it is either. It is a property of
concepts. Although the traditional English use of the word of
emergence implies a process occuring through time, this only comes
about because of a picture of "moving" from a microscopic description
to a macroscopic description.

                                        Cheers

> The process terminates when we say that something "has emerged", meaning 
> that the particular pattern has become *common* or *diffuse*.
> But the main object of our studies on emergence is "how something
> begins to emerge, under which conditions ..."
> Economists study how can recession emerges, the article mentioned above
> (among other things) try to explain why cooperation emerges after 
> defection etc.
> 
> So at this point I propose this draft of definition:
> "Emergence is a process that brings the observer of a system described
> with a macro and micro language, to observe a common pattern. The 
> pattern is described with micro and macro language and, if not previosly 
>  defined by the languages, this process add new concepts at the 
> languages used for the system."
> 
> 
> With regard to postings about the interaction between agents and the 
> environment, my humble opinion is that the environment is nothing but
> an agent itself: it has a description, a behavior and so on.
> 
> Comments will be welcome, 
> 
> Matteo Piombo
> 
> Universita' di Padova (DIMEG)
> Padova (PD)
> 
> 
> 
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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             
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   please send a message to <address@hidden> with "help" in the
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