There are at least two crucial differences between a biological system and
an artificial one.
1- The first is built top-down, the second bottom-up. Embryogenesis
begins by a unique cell, which differentiates into tissues and organs.
This espablishes a peculiar causal regimes, where various levels of
organisation are causally entangled since the beginning (regulation,
integration fluxes). So far, we are only able to construct artificial
systems by assembling parts, from bottom. And this is probably inherent to
the very notion of (human) designed system.
2- All our machines are cartesian: they are made possible (and
intelligible) by assemblying simple parts,
which may lead to extremely complicated artefacts. Then the elementary is
simple, as Descartes wanted us to decompose beings (and reasoning).
Complexity, in natural systems, begins with the elementary components,
which may be very complex. A single living cell is elementary (if
decomposed, it is dead), but it is extremely complex.
One could also observe that it is exactly this elementary component of
live that in no way we can reproduce.
We are able to construct organs of all sorts, and even assembly
them, but not a single cell, with its top-down generating process.
I think that this is compatible with the great refections by Robert Rosen.
More may be downloaded from my web page.
Giuseppe Longo
Laboratoire et Departement d'Informatique
CNRS et Ecole Normale Superieure
et CREA, Ecole Polytechnique
(Postal addr.: LIENS
45, Rue D'Ulm
75005 Paris (France) )
http://www.di.ens.fr/users/longo
et :
CENtre d'Etude des systemes Complexes et de la Cognition (CENECC)
http://www.cenecc.ens.fr/
e-mail: longo@di.ens.fr
(tel. ++33-1-4432-3328, FAX -2156, secr. -2059)
Upon kind permission of the M.I.T. Press, the book below is
currently downloadable from Longo's web page above (its n-th
edition is out of print...):
Andrea Asperti and Giuseppe Longo. Categories, Types and
Structures: an introduction to Category Theory for the working
computer scientist. M.I.T.- Press, 1991. (pp. 1--300).
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Received on Wed Jan 25 09:18:02 2006
