RE: [Fis] cell signaling: COMMUNICATION

Dear Pedro,

It seems to me that the demand to produce "molecularly based" responses to
those questions lke info, signal, meaning, etc., makes it virtually
impossible to answer them. Information (probabilistic entropy) is first a
mathematical concept that is dimensionless (e.g., bits of information).
Thus, it is a property that emerges within the model and that does not in
itself refer to a natural quality. For this reason, tt is very different
from thermodynamic entropy that has a dimension (Watt/Kelvin).

For example, when billiard ball collide they produce no entropy in the
ideal case (since the collision is perfect). However, in this case the
exchange of energy and momentum is maximal. Thus, the production of
probabilistic entropy in the change of these distributions is also maximal.
When the friction in the collision increases, the probabilistic entropy
paradoxically decreases. Thus, the two concepts of entropy and
probabilistic entropy are analytically independent (but one can use the
same formalisms).

In other words, the information dynamics have first to be specified in
terms of relevant probability distributions produced by the molecular
processes. The specification of the system of reference may then be
orthogonal to the "natural" one as the above example illustrates. I can
work this out for chemical systems, but I haven't done it for (molecular)
biological ones. Brooks & Wiley (1986) "Evolution as Entropy" go a good
stretch in that direction.

With kind regards,

Loet Leydesdorff

        -----Original Message-----
        From: "Pedro C. Marijuán" [mailto:marijuan@posta.unizar.es]
        Sent: Thu 10/2/2003 8:51 PM
        To: fis-listas.unizar.es
        Cc:
        Subject: Re: [Fis] cell signaling: COMMUNICATION
        
        

        Dear Soeren,
        
        Thanks for the comment. I largely agree with it. The informational
        understanding of the cell is a big problem for a variety of disciplines and
        approaches (though contemplated in a very different guise by each one). I
        think that at the time being we cannot produce consistent 'molecularly
        based' responses to those questions --info, signal, meaning, biosemantics,
        etc.
        
        For instance, we may agree that the 'phase' (running towards completion of
        a 'cycle') is the time-binding-reference of the living for its
        informational coupling to the boundary conditions --and not the 'state',
        characteristic of the mechanical coupling. But, then, a fantastic
        multiplicity of different enzyme pathways (e.g., metabolic ones) may be
        used to transverse the phases (to arrive into what the cycle biologists
        call the 'checkpoints')...
        
        How could we formulate -- with some formal elegance-- the enormous
        redundancy, robustness, and resilience that the informational coupling of
        the living to its boundary conditions purports? The challenge of the neat
        formulation of mechanics is in front of us. This formal problem is shared,
        I think, by other disciplines leading with complex existentialities whose
        survival also depends on a continuous communication with its environment
        (eg, companies).
        
        best
        
        Pedro
        
        At 10.18 30/9/03 +0200, you wrote:
>Dear Pedro
>
>You are getting closer and closer to Biosemiotics in your overall view.
>But we need to distinguish between information and meaning (bio-psyc and
>psyc.-social), signal, sign and language. To me the informational mostly
>starts with the chemical because here the pattern fitting becomes the
>most important form of interaction.
        
        _______________________________________________
        fis mailing list
        fis@listas.unizar.es
        http://webmail.unizar.es/mailman/listinfo/fis
        

_______________________________________________
fis mailing list
fis@listas.unizar.es
http://webmail.unizar.es/mailman/listinfo/fis
Received on Fri Oct 3 11:54:55 2003