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=66 you 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 Gödel 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, Günther -- Günther Greindl Department of Philosophy of Science University of Vienna [EMAIL PROTECTED] http://www.univie.ac.at/Wissenschaftstheorie/ Blog: http://dao.complexitystudies.org/ Site: http://www.complexitystudies.org ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
