Re: Life versus computers

[Judith Rosen <***>]

Howard, in re-reading your last post, I realized I have to respond to the
following, which I did not include in my last reply.  The statement below is
a complete mischaracterization of what my father's entire body of work
stands for:

>Howard Pattee wrote:  Rosen's example of what he means by a maximally
constrained is the special purpose computer; that is, a machine that
computes one function, like a particular Turing machine. Even a programmable
computer is maximally constrained because its sequence of states has maximal
dependence on the program constraints and minimal dependence on laws. Laws
depend on energy, time, and rates that do not play essential roles in
computing a function. Also, no new parts are constructed. >

I think you have completely misinterpreted the entire thrust of his
argument. Anyone who can equate what he was saying with "life is like a
computer" is not getting it. Indeed, half the arguments on this list and
elsewhere with his work are over his statement that complete computability
is synonymous with a "simple system". One of his definitions of a complex
system (nevermind a living system, which is at the extreme end of the
complexity spectrum) is that a complex system must possess at least one
non-computable model. So,  you have apparently turned his words around in
your head until they mean the exact opposite of what he actually meant, and
then you state:

>(HP): In my view computers are nothing like life. >

What's up with that?!? Are you honestly trying to say that Robert Rosen's
view differs from yours on this issue???

In a secondary, parenthetical issue, I think you are defining "constraints"
in inconsistent ways, as can be seen in the following statement from the
same post:

> (HP): Unlike computers, all the functions of life depend on energy, time,
and rates. Folding and self-assembly processes are minimally constrained
energy minimizations or relaxation processes. Metabolism and replication
depend on specific rate control. Enzymes are the universal rate-controllers.
It is a simple fact that the genetic sequences constrain only a tiny
fraction of the enormous number of variables (degrees of freedom) of
biopolymers. New parts are continually constructed.>

That first sentence describes a whole pile of holonomic and non-holonomic
constraints, from where I'm sitting. The second sentence contradicts the
first and is incorrect, in my opinion. The third sentence contradicts the
second by specifically mentioning unspecified types of constraint in
"specific rate control". The fourth sentence is a non-sequitur (how did
genetics get into this paragraph?). It also happens to echo a sentiment that
my father stated many times about genetic influences on living systems
(which, I suppose includes "biopolymers"). You state it as if he would
disagree with you, but his work ought to reassure against any such fear.

Finally, there is this statement to discuss:
> (HP): Rosen (in this paper) does not distinguish life in these terms but
by the inequivalence of programs (simulations) and causal structures.>

There is no need to argue this one and I would not even need to read the
paper to know that it is consistent with his modus operandi. The point you
are missing is that there are many, many ways to "distinguish" life from
non-life. He came up with a large number of ways, and he laid out every
single one in separate arguments. The statement above (that programs and
simulations are not equivalent to the causal structures underlying the
behavior of living systems) says categorically that life is not like a
computer!

You are a frustrating man, Howard.

Judith