Re: Life without evolution/evolution without life

[Tim Gwinn <***>]

Howard,

Thanks, that helps alot. I wish the von Neumann works were more readily
available (at reasonable prices!). I do have Burks' "Essays on Cellular
Automata", I'll try to see if I can pick up some more from that.

Regarding Rosen's continued objections to von Neumann, my understanding was
that Rosen's more general objection had to do with the realization issue
itself. Namely, that the inequivalence of causal categories (material and
efficient, specifically) meant that von Neumann's approach could not be
physically implemented and that the approach was therefore of questionable
import:

"Now a computer acts, in the language we have developed above, through the
manipulation of efficient cause. A constructor, if the term is to have any
any shred of its intuitive meaning, must essentially manipulate material
cause. The inequivalence of the two categories of causality, in particular
manifested by the non-equivalence of environmental and phenotypic
information, means that we cannot blithely extrapolate from results
pertaining to efficient causation into the realm of material causation.
Indeed, in addition to invalidating von Neumann's specific argument, we
learn that great care must be exercised in general when arguing from purely
logical models (i.e., models pertaining to efficient cause) to any kind of
physical realization, such as developmental or evolutionary biology (which,
as noted, pertain to material cause)." [AS, 419]

By contrast, I think that since the (M,R)-system explicitly delineates the
distinct causal categories in it's representations, that Rosen felt it must
have avoided this dilemma.In fairness, as you point out, von Neumann did not
proclaim he knew how to generate a material realization of his ideas, so
Rosen's remarks are not really a refutation of a claim but rather a
confirmation of the concerns von Neumann himself apparently expressed
regarding bridging the wide gulf between formal representation and material
realization.

Would Rosen's criticism, though, touch upon the other point of von Neumann's
regarding the need for the two disjoint categories of components
("constructions" and "quiescent descriptions")?  I don't know enough about
the details of the argument.

Regards,
Tim

P.S. - The "Causal Structures" paper by Rosen is one that I have been
seeking. (Any luck yet locating it, Judith?)

> -----Original Message-----
> From: ROSEN Forum [mailto:*** Behalf Of Howard
> Pattee
> Sent: Monday, March 22, 2004 10:17 AM
> To: ***
> Subject: Re: Life without evolution/evolution without life
>
>
> Tim,
>
> You have to begin by asking: What is the question that von Neumann is
> trying to answer? And also: What questions is he NOT trying to
> answer? Also
> you must remember that in Theory of Self-Reproducing Automata (von N) are
> informal transcribed lectures with the editor, Burks, filling in large
> sections. Von Neumann?s discussions of self-reproduction extended over 4
> years, so there are some differences of emphasis. One needs to read the
> whole story. An additional source is his Hixon Symposium (von N, HS) talk
> (Vol 5, No. 9, Jeffress, ed., Wiley, 1951).
>
> Von Neumann?s fundamental question is: What is the threshold of complexity
> of a system that can evolve increasing complexity rather than degrade?
> Increasing complexity can be interpreted broadly as open-ended emergence,
> endless variety, or evolutionary novelty.
>
> He concludes that this will require a type of self-reproduction, and this
> requires more than a symbolic Turing machine. He says, ?For the question
> which concerns me here, that of self-reproducing automata, Turing?s
> procedure is too narrow in one respect only. His automata are purely
> computing machines. Their output is a piece of tape with zeros and ones on
> it. What is needed for the construction to which I referred is an
> automaton
> whose output is another automaton.? (von N, HS p. 315)
>
> Consequently, he warns that with respect to his choice of parts for the
> automaton: ? . . . this choice is neither rigorously justifiable nor
> humanly unambiguously justifiable. All one can do is to try to submit a
> system that will stand up under common sense criteria.? (von N,
> p. 77) That
> is, it is not a formal logical argument as Rosen incorrectly
> assumes in his
> critique.
>
> What von Neumann did NOT ask was about physical implementations. As von
> Neumann warns, ?One has resigned oneself not to explain how these
> parts are
> made up of real things, specifically, how these parts are made up
> of actual
> elementary particles, or even higher chemical molecules.? However, unlike
> Rosen, he doubts that a relational model alone is adequate. In
> constructing
> a relational (?axiomatic?) model, he says, ?One does not ask the most
> intriguing, exciting, and important question of why the molecules or
> aggregates which in nature really occur are the sorts of things they
> are . . .? (von N p. 77)
>
> I?ll skip von Neumann?s ?common sense? derivation here (I?ll do
> it later if
> you wish). His essential conclusion is that even entirely abstract
> relational models of replication require two disjoint categories of
> components: 1) components that can be described temporally by a dynamics
> (?constructions?), and 2) components that are non-dynamic structures
> (?quiescent descriptions?) that can be described as memory-stored symbolic
> constraints on the dynamic constructions.
>
> Von Neumann did not discuss the physical conditions necessary for symbolic
> descriptions. He simply assumed that his abstract concept could be
> materially implemented. I took up the problem of the physical requirements
> for implementing symbolic descriptions, and this is what led to Rosen and
> my discussions of Hertz and his modeling relation. (My intellectual
> dependence on von Neumann is described at
> http://wwwc3.lanl.gov/~rocha/pattee/pattee.html) The best single Rosen
> paper for illustrating how we agree and disagree is Causal Structures in
> Brains and Machines, Int. J. General Systems 12, 107-126, 1986. Also this
> paper most clearly shows how he misinterprets von Neumann (p. 114).
>
> Von Neumann?s admittedly incomplete discussions of replication are often
> credited as the beginnings of artificial life studies as well as
> a stimulus
> for the discipline of biosemiotics.
> I would emphasize that Von Neumann?s conclusion is entirely
> consistent with
> Rosen?s conclusion that dynamics alone (the generalized Newtonian
> paradigm)
> is too restricted to describe life, and that complex systems require more
> than one model. However their logics and levels of abstraction are quite
> different. Von Neumann is actually making what I think Rosen recognized as
> a relational model that competed with his own (M,R) ? systems. They are
> both abstract models that do not employ any particular material
> representation, but that would hold for any material embodiment.
> This might
> explain Rosen?s motivation for continually objecting to it on the same
> grounds for over 30 years.
>
> Howard