Posted by
Günther Greindl on
URL: http://friam.383.s1.nabble.com/Welcome-Jim-tp526087p526104.html
Dear Glen,
> [grin] That's not an answer to my query. You said that the recursion
> theorem _refutes_ RR's claim. You can't just say "I don't see how RR's
> claim is justified." That's not a refutation. It's just a simple
> statement that you don't know the justification.
Sorry, I did not answer directly, that is true.
Of course, you have to be careful when criticising Rosen, as most
critics are then countered by "that is not how RR uses that and that word".
For instance, here:
http://www.panmere.com/?p=66you read:
"However, Wells fails to understand that Rosen is constructing a
specific and unequivocal definition of ?machine? - Rosen is not
attempting to utilize some vague colloquial definition of ?machine?."
The thing is: when computer scientist talk about "machine", it is
perfectly well defined: they talk about a Universal Turing Machine (or a
TM and it's equivalents, whatever you like).
So, when I speak of machine/mechanism I mean the general, computer
science meaning; also, recursive functions are well defined, no problems
in this area.
More problematic of course is life: I guess there is no single accepted
definition of life, people will not even agree on what is alive (virus? etc)
So, maybe Rosen has a personal definition of life, but what I targeted
was the (M,R)-systems, which he posits as a model of organism which are
opposed to mechanisms.
And I can't see anything in (M,R)-system (metabolism, repair) which is
not amenable to a mechanistic solution, the only real difficult part
being the coding of the replication of the system from within itself -
and that is where the recursion theorem comes in.
So my argument runs as this: the models Rosen proposes as models of life
can be modeled by well known mechanistic models. Hence Rosen's claim
that life is not a mechanism is refuted.
One objection may be that if life is a mechanism, then why doesn't Alife
work out as we would like? Of course, life is a very _complicated_
mechanism. It uses all kinds of natural laws down to quantum phenomena
(Van der Waals Forces in Geckos, as a famous example). So maybe life
can't be captured by simplistic mechanism (meaning, sequential, slow
processing with no relationship to real environment)
What I argue against is this fundamental dichotomy which is trying to be
interposed between living beings and non-living beings; I find RR's
theories fruitful insofar as he proposes new modeling techniques. I find
them counterproductive as he argues against mechanism.
But, as said above, it seems that RR defines mechanism differently. This
is of course very unfortunate, as it will have people talking past each
other. Unfortunate also because mechanism is indeed a word which can be
given a precise, mathematical meaning.
Concerning argueing against mechanism:
Something similar also happens in the domain of mind: the Lucas-Penrose
argument that G?del Incompleteness implies a non-mechanistic view of the
mind. (Glen, we had a similiar discussion some time ago ;-)
While this claim has been shown to be without substance, but still
circles around due to public appeal (?), there is indication that rather
the contrary holds; (Incompleteness implies mechanism) see this book for
instance:
Mechanism, Mentalism and Metamathematics: An Essay on Finitism (Synthese
Library) by J. Webb
http://www.amazon.com/Mechanism-Mentalism-Metamathematics-Finitism-Synthese/dp/9027710465/ref=sr_1_1?ie=UTF8&s=books&qid=1208976075&sr=8-1(Very expensive :-((, maybe your library has it?)
Bruno Marchal (
http://iridia.ulb.ac.be/~marchal/) alerted me to the
astounding and beautiful consequences of mechanism applied throughout;
and the philosophical chasms opening when not doing so.
Cheers,
G?nther
--
G?nther Greindl
Department of Philosophy of Science
University of Vienna
guenther.greindl at univie.ac.at
http://www.univie.ac.at/Wissenschaftstheorie/Blog:
http://dao.complexitystudies.org/Site:
http://www.complexitystudies.org