Dear Pedro, 


You are right: the dimensionality of thermodynamic entropy is Joule/Kelvin.

Probabilistic entropy/uncertainty/information is dimensionless and measured
in bits.


Configurational information (a point of access to measuring meaning) is also
measured in bits, but it is not a Shannon entropy (Krippendorff, 2009). It
can be considered as a redundancy = reduction of uncertainty = a difference
which makes a difference.






Loet Leydesdorff 

Professor, University of Amsterdam
Amsterdam School of Communications Research (ASCoR), 
Kloveniersburgwal 48, 1012 CX Amsterdam. 
Tel.: +31-20- 525 6598; fax: +31-842239111  <> ; ;
<> &hl=en 


From: [] On
Behalf Of Pedro C. Marijuan
Sent: Wednesday, April 11, 2012 10:44 AM
Subject: Re: [Fis] Physics of computing


Dear John and colleagues,

Nice to hear that you are OK after that dangerous intoxication --our best
wishes for your complete recovery! 
About physical information I think that Landauer clarified the panorama, at
least concerning the relationship between information theory and
thermodynamics. According to his principle, any logically irreversible
transformation of classical information is necessarily accompanied by the
dissipation of at least k T ln(2) of heat per lost bit (about 3 x 10 exp -21
Joules at 300 K temperature), where obviously k is the Boltzmann constant
and T the temperature. Recently this principle has been verified
experimentally (Nature, 8 March 2012, p. 187). By the way, in his past
message Loet enters "Watts" in a similar expression (?). To insist, Entropy
and Information are dimensionless and do not explicitly incorporate any
units... About the quantum management of info theory, it is another matter,
quite more tricky. 

Beyond that immediate physicality, things get quite obscure as our
contradictory "meaning" messages witness. The point made by Joseph on an
overarching logic, is rather difficult to be maintained --at least in my
small province of the biological signaling pathways. Too many logics are
used biologically in too many different contexts or niches, either
molecularly or neuronally... I bet that they are not susceptible of
integration in any logical system.  Maybe Inbiosa parties would also
disagree with me in this regard.

best wishes to all,


John Collier escribió: 



I have been in the hospital for almost three weeks due to bleeding from
warfarin. I had to have three blood transfusions and an operation. I am only
now getting my strength back. Some of my comments, therefore, may be dated.


"Physical" has a variety of overlapping meanings (a Wittgensteinian family
resemblence). For example Quine takes the physical to be anything accessible
to the senses or inferences therefrom. Ladyman, Ross, Collier an Spurrett
take the physical to be the most fundamental laws of our (part of) the
universe. I did not agree with this, among some other crucial points, so I
was not a primary author. Information is at least physical in both of these
senses. Quine's approach might make it entirely physical. I prefer to relate
it to the causal, which always has physical parametres, as far as we know.
But there are many ways of approaching this issue, and disentangling them
will be a major advance in foundations of information theory.


My Best,



Professor John Collier  
Philosophy, University of KwaZulu-Natal
Durban 4041 South Africa
T: +27 (31) 260 3248 / 260 2292
F: +27 (31) 260 3031
email:>>> On 2012/03/16 at 01:19 PM, in message
<> <>, "Pedro C.
Marijuan"  <> <>

Dear discussants,

I tend to disagree with the motto "information is physical" if taken too
strictly. Obviously if we look "downwards" it is OK, but in the "upward"
direction it is different. Info is not only physical then, and the dimension
of self-construction along the realization of life cycle has to be entered.
Then the signal, the info, has "content" and "meaning". Otherwise if we
insist only in the physical downward dimension we have just conventional
computing/ info processing. My opinion is that the notion of absence is
crucial for advancing in the upward, but useless in the downward. 
By the way, I already wrote about info and the absence theme in a 1994 or
1995 paper in BioSystems...


---Pedro escribió: 

Thanks John and Kevin to update issues in information, computation, energy
and reality.

 I would like point out to other articles more focused in how coherence and
entanglement are used by living systems (far from thermal equilibrium): 


Engel G.S., Calhoun T.R., Read E.L., Ahn T.K., Mancal T., Cheng Y.C.,
Blankenship R.E., Fleming G.R. (2007) Evidence for wavelike energy transfer
through quantum coherence in photosynthetic systems. Nature, 446(7137):


Collini E., Scholes G. (2009) Coherent intrachain energy in migration in a
conjugated polymer at room temperature.  Science, vol. 323 No. 5912 pp.


Gauger E.M., Rieper E., Morton J.J.L., Benjamin S.C., Vedral V. (2011)
Sustained Quantum Coherence and Entanglement in the Avian Compass. Phys.
Rev. Lett., 106: 040503.


Cia, J. et al, (2009)  Dynamic entanglement in oscillating molecules.
arXiv:0809.4906v1 [quant-ph]










fis mailing list

Pedro C. Marijuán
Grupo de Bioinformación / Bioinformation Group
Instituto Aragonés de Ciencias de la Salud
Avda. Gómez Laguna, 25, Pl. 11ª
50009 Zaragoza, Spain
Telf: 34 976 71 3526 (& 6818) Fax: 34 976 71 5554


Please find our Email Disclaimer here-->:



fis mailing list

Pedro C. Marijuán
Grupo de Bioinformación / Bioinformation Group
Instituto Aragonés de Ciencias de la Salud
Avda. Gómez Laguna, 25, Pl. 11ª
50009 Zaragoza, Spain
Telf: 34 976 71 3526 (& 6818) Fax: 34 976 71 5554
fis mailing list

Reply via email to