Re: Dynamical Hierarchies

[Judith Rosen <***>]

Hi David,

Interesting post!

I wonder how they mean it when they use the word "dynamical"? In my father's usage, dynamical has a particular, very specific meaning. Dynamical systems are simple systems; fully computable (reducible to syntax). They can be addressed via physics, using state descriptions, etc. The more prosaic meaning for "dynamical" tends to mean "constantly interactive and interacting, and therefore undergoing constant change" which is a completely different animal. That usage, and the further description in the clip David posted, seem more to be describing complex system behavior.

But I think the situation is even more difficult than they apparently perceive. In the quote:

"<x-tad-smaller>A typical example in this context is the functional differences between proteins and their building blocks, amino acids.  The functionality of proteins is not directly the result of the properties of the individual amino acids. "</x-tad-smaller>

The functionality (of proteins) is equally not the result of the entire protein, either. The protein is not capable of functional activity until it assumes its folded shape. Even then, it is further true that the protein's functionality is not just because of the folded shape. Instead, the protein's functionality is  a result of the interactions between the folded shape and other aspects of the organism and environment. So all of the previous development of the protein is part of the context for this eventual interaction... Stated another way: The future interactivity (functional capability) of the protein is what drives all of the previous development. That's anticipation, which must be part of the model they seek to build. 

But they have achieved a lot here. They clearly perceive that relations between components are of critical interest in modeling organismal behavior, as well as the further fact that direct relations are not the only critical ones in organisms. This represents some much needed, really important progress in science. 

Do they, however, recognize the significance of it, with regards to the machine metaphor and the accompanying state-based model of the universe? 

Judith


Web address: http://www.rosen-enterprises.com
BioTheory: An electronic journal of general science based on the Relational (Rosennean) Complexity Paradigm
On Oct 5, 2005, at 11:20 AM, David Macy wrote:

> <x-tad-smaller>Hey Guys,</x-tad-smaller>
>  
> <x-tad-smaller>    I have here in front of me a copy of Artificial Life, volume 11, number 4.  The issue is devoted to dynamical hierarchies.  I thought that I would type in a part of the guest editors' introduction to see what (if anything) you guys might have to say about it.  I generally like these guys at Artificial Life.  They are an eclectic and very cross-disciplinary crowd.</x-tad-smaller>
>  
> <x-tad-smaller>The guest editors are as follows:  Tom Lenearts, Dominique Chu, and Richard Watson.</x-tad-smaller>
>  
> <x-tad-smaller>The first paragraph of the introduction is as follows...</x-tad-smaller>
>  
> <x-tad-smaller>In "Open Problems in Artificial Life", </x-tad-smaller><x-tad-smaller>Artificial Life</x-tad-smaller><x-tad-smaller>, volume 6 (number 4), pgs. 363-376, Mark Bedau et al. proposed a set of fourteen open problems in artificial life.  The content of this special issue specifically addresses one of those suggested problems: </x-tad-smaller><x-tad-smaller>How can we create a formal framework for synthesizing dynamical hierarchies at all scales?</x-tad-smaller><x-tad-smaller>  The dynamical hierarchy concept refers to a system that consists of multiple levels of organization having dynamics within and between the entities described at each of the differing levels.  An important aspect of this concept is the fact that entities at different levels can have different functionalities that emerge from the interactions of the lower-level units.  In other words, dynamical hierarchies define a system that is structured by part-whole relationships between objects, where each whole can exhibit properties and can interact in ways different from its parts.   As a consequence, the complete system needs to be modeled as structures relating different description levels of dynamical systems and their interconnectedness.  A typical example in this context is the functional differences between proteins and their building blocks, amino acids.  The functionality of proteins is not directly the result of the properties of the individual amino acids.  The overall protein structure plays a crucial role here.  As a consequence, properties that amino acids do not exhibit in their solitary state can be exhibited collectively.  The same observations can be made when moving from solitary proteins to the level of protein-protein interactions.  New functionalities emerge as a result of the different complexes produced by these interactions.  It is the combination of all these dynamical levels from amino acids to multicellular organisms that makes it a dynamical hierarchy and not merely some simple single-level emergent phenomenon.</x-tad-smaller>
>  
> <x-tad-smaller>Well there it is.  I hope that you all are doing well.</x-tad-smaller>
>  
> <x-tad-smaller>David</x-tad-smaller>