On Thursday 02 April 2009, Pedro C. Marijuan wrote: > It conduces to realizing that the > information processing of living cells is not of the same class than the > processes of formal, predicative nature (computation).
Why computational processes should be necessarely predicative? Girard's Type Theory (System F) is impredicative yet "fully computational" (it computes exactly the recursive functions provably total in second order Arithmetic). A detailed critique of Rosen's analysis is in: Matteo Mossio, Giuseppe Longo, John Stewart. Computability of closure to efficient causation. To appear, J. of Theoretical Biology, 2009. (ftp://ftp.di.ens.fr/pub/users/longo/CIM/comp-closure.pdf). > Rather, > biomolecular processing is a “tactilizing” phenomenon based on a myriad > of specific “molecular recognition” events (Conrad, 1998; Marijuán, > 2003); yes, this is the point: the structure of interactions, also beetwen different and entangled levels of organization, poses major modelling problems, well beyond the computational or the (minor) impredicativity issue (e. g. incompatibility between type-free and differentiable manifolds). Rosen was wrong on the circularity and impredicativity issue, yet he was right as for the global perspective (see the above paper). Giuseppe Longo http://www.di.ens.fr/users/longo Laboratoire et Departement d'Informatique CNRS et Ecole Normale Superieure et CREA, Ecole Polytechnique _______________________________________________ fis mailing list email@example.com https://webmail.unizar.es/cgi-bin/mailman/listinfo/fis