Re: What is emergence?

[address@hidden]

> Consider a system described by 2 languages which we call "microscopic"
> and "macroscopic". Furthermore, we suppose that the system is
> completely described by the microscopic language - true in the case of
> an agent based simulation for example, arguably less true of a real
> world system, where the microscopic description is probably expressed
> in terms of an approximation like classical mechanics.

> If some concept or property in the macroscopic language is not
> contained within the microscopic description, then it is emergent. 

I am very interested in this approach to emergence, but it seems to me
that the term language might not be really appropriate, or might be well
defined.
I think that emergence concerns more with concepts, phenomena and 
perceptions.
At firts we must observe that the micro and macro world must have some
relation. We might try to define this relation as "class and subclass".
So any element in your microworld must be defineble, in some way, as
belonging to a subclass of the macroworld (class).
We can recognize emergence only when we can "percive" it, thus we need
an "observer".
Now we have a macroworld (class) built on microworlds (subclasses)
interacting, and an *external* observer.

I think that what you mean with langage, is the definitions of 
subclasses properties and their interactions.
Thus a new concept or property in the macroworld langauge is just
a new way to define the class. This is done by the observer (an upper
class) *after* the perception of the need of a new concept or property.
You can't speak about temprature if you can't feel the difference 
between hot and cold.

So i think that we might say that emergence occours when the observer
recognize a "pattern" while observing the class.
In the case of temprature the pattern might be mean energy.

This approach might be more general since it allows emergence in the
microworld.
When the water boil (the macro property "temperature" goes above 100°C)
something "new" emerges even in the microworld.
In a social environment emergence happends even at the individual level.
So we can speak about number of men, wemen, children, births, deaths
... at the macro level, but some "new" behaviour may "emerge" and become 
common at the microlevel. This behavior will than be described with
the microworld language.

Any feedback will be welcome.

Matteo

Universita' di Padova (DIMEG)
Padova (Italy)



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