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Re: Could you give me your analysis of this?
- From: Tim Gwinn <***>
- Date: Sun, 12 Sep 2004 12:59:58 -0400
In response to
Aloisius' remarks, the two following things stand out in my mind after
thinking about it this weekend:
1) I consider
the statement (Q1) from Life Itself:
"The answer we
propose is now this: a material system is an organism, if an only if, it
is closed to efficient causation." [p. 245, ital.
orig.]
to be updated
in the later book Essays on Life Itself by (Q3 and Q4):
"From this point
of view, then, a cell is (at least) a material structure that
realizes an (M,R)-system, under the condition that at least one of the
appropriate inverse evaluation maps exists. Making a cell means
constructing such a realization. Conversely, I see no grounds for
refusing to call such a realization an autonomous life form, whatever its
material basis may be." [p. 263, ital. orig.]
I think that the
original criteria proposed in the definition in Life Itself was too broad, both
as a necessary and as a sufficient condition. There may be examples of material
systems which are closed to efficient causation but which are not alive.
In that case, as a necessary condition (a material system is an organism
only if it is closed to efficient causation, or reworded: IF a material
system is an organism THEN it is closed to efficient
causation), it does tell us an important quality of organisms, but it
would not provide a useful defining characteristic of just
organisms.
As a sufficient condition (a material
system is an organism if it is closed to efficient causation, or
reworded: IF a material system is is closed to efficient causation THEN it is an
organism), this would clearly be incorrect if there are indeed material
systems which are closed to efficient causation but which are not alive.
On the old VCU COMPLEXITY-L list I know there has been several comments by
listmembers that Don Mikulecky and others had presented examples of such
systems which are closed to efficient causation but which are not alive,
although I cannot find such examples at the moment (anyone have any links or
examples from those days?).
By contrast, the remarks in Essays refer not to material realizations
of just any closed-to-efficient-cause organization, but specifically to
realizations of members of one specific class of closed-to-efficient-cause
organization models: (M,R)-system models. In this sense, I consider Q3&Q4 to
be a refinement of the necessity condition proposed in definition
Q1.
Further, this would also mean that "closed to efficient causation" is no longer
considered a sufficient condition, which is borne out by Q2. In that sense, I
consider Q3&Q4 to be a retraction of the "closed to
efficient causation" sufficiency condition in Q1.
2) I have always
been puzzled by - what I consider to be - a deep conflict between
Rosen's proposing of sufficient condition in Q1 and the "Godelian
suggestions" (as Aloisius puts it) evident in Q2 that "Sufficient
conditions are harder; indeed, perhaps there are
none".
Clearly, Rosen was well aware of the Godelian implications
for decidability of sufficiency conditions long before he wrote Q1 in
Life Itself. So, I have always been puzzled why Q1,
and the discussion surrounding it in that chapter, did not qualify the
sufficiency condition in any way. Particularly if, as Aloisius suggests,
Rosen saw it as a case of a necessary condition being "so close" to being a
sufficient condition "that one may as well ACCEPT, or BELIEVE, that it is
so", rather than for some more rigorously defensible
reason.
As such, I do see the tenor of the sufficiency statement in Q4 as being a
"softening", to put it mildly, from his sufficiency statement in Q1.
Actually, in the way he phrases it using double negatives ("...I
see no grounds for refusing..."), I would argue that it does not constitute a
sufficiency condition at all. The assertion "I see no grounds for refusing
to call such a realization an autonomous life form, whatever its material
basis may be" is not at all the same as the assertion 'I see grounds
for calling such a realization an autonomous life form, whatever its
material basis may be'. I think his wording was precisely chosen so as to
suggest a possible locus for a sufficiency condition without actually asserting
one.
I'd be curious
what Aloisius thinks of these comments.
Regards,
Tim
The following is a response I received (along with permission to
post it) to some comments made about my father's work. I thought both
discussion "lists" would benefit from reading it.
The analysis was generated by Dr. Aloisius Louie, one
of my father's PhD students at Dalhousie University in the early 1980's who is
a friend of mine. I don't have permission to reproduce the comments I wanted
his analysis of, themselves, but the gist of what was asserted is as
follows: 1.) Did my father retract any of the seminal definitions of earlier
books in the work published in the book; "Essays on Life, Itself"? (He
himself had stated to me, when I once asked him this question, that he
did not retract anything but instead had refined the details.) 2.) If someone
were to develop an algorithm which "completely characterizes" the M-R
(metabolism-repair) process, does that collapse my father's theoretical basis?
I was intuitively inclined to believe that it does not collapse
the work if someone can "compute" some process of life in an organism, any
more than mapping a sphere with planes changes the fact that you're mapping a
sphere! However, I don't have the math training to be able to discuss my
father's work in mathematical terms. Aloisius, however, DOES have
the training and the talent to do so. I was gratified to see that my intuition
is backed up by the math. The analysis is reproduced
below.
Judith
PS: Incidentally, there was also a question about whether it is
still useful to create computer models of living processes if my father's
assertion that "complex systems are not computable" holds true. I think it is
important to point out that my father talked about this in nearly all his
books, at great length. And he concluded that it IS still valuable, still
useful, even ESSENTIAL to model complex systems as long as our models of
complex systems are constructed with a relational mindset-- regardless of
the mode we use. A relational mindset at the very least ensures that we never
mistake the model for the system.
> Dear Judith:
>
> I know we will come back to this “necessity versus sufficiency” issue
> sooner or later. As I look at my marginal notes I made in “Life
Itself”
> and “Essays on Life Itself”, I see that quite a few of them
are about
> “necessity versus sufficiency” in one form or
another.
>
> Let’s backtrack a bit, and list three quotes from
Bob:
>
> Quote 1. A material system is an organism if, and
only if, it is closed to
> efficient causation. (p.244 of “Life
Itself”, Section 10A. The Answer)
>
> Quote 2. To be sure,
what I have been describing are necessary conditions,
> not sufficient
ones, for a material system to be an organism. That is,
> they
really pertain to what is not an organism, to what life is not.
>
Sufficient conditions are harder; indeed, perhaps there are none. If
> so, biology itself is more comprehensive than we presently
know. (p.28
> of “Essays on Life Itself”, Section on What Is
Life?)
>
> Quote 3. A cell is (at least) a material
structure that realizes an
> (M,R)-system. (p.263 of “Essays on
Life Itself”, Section on The
> (M,R)-Systems)
>
> Q1 is a
statement of both necessity (the “only if” part) and
> sufficiency (the
“if” part). Q2 is self-explanatory. Q3 is a statement
> on
necessity (the “at least” part is an emphasis on this
>
“necessary-but-not-sufficient” condition).
>
> In my retort of
the Landauer-Bellman paper (that I sent you a few
> months ago), I
wrote “Landauer and Bellman are confused between
> necessity and
sufficiency. The Rosennean statement is that "a cell is a
>
material structure that realizes an (M,R)-system". This is a statement
> of necessity. It means that if C is a cell, then THERE EXISTS
an
> (M,R)-system S such that C realizes S. It does NOT mean that
if one
> comes up with an arbitrary (M,R)-system (or worse, something
that only
> vaguely resembles an (M,R)-system), there has to be a cell
that realizes
> it. "If C, then S" (S is necessary for C), is not
"if S, then C" (S is
> sufficient for C).” I was, of course,
using Q3 there.
>
> I have not kept up with the literature and
debates on the subject, so I
> wouldn’t know what the “five authors,
Landauer, Goertzel, Casti,
> Wolkenhauer, and McMullin” did.
Well, the last four anyway, if this
> “Landauer” is the same one as in
the Landauer-Bellman paper.
> I don’t know what [this
person] meant by “completely characterizes the M-R
> process”; but
as I said, “It does NOT mean that if one comes up with an
> arbitrary
(M,R)-system (or worse, something that only vaguely resembles
> an
(M,R)-system), there has to be a cell that realizes it.”
>
> Note
that even if Q3 were stated in the necessary-and-sufficient form:
>
> Q3'. A material structure is a cell (i.e. alive) if and only if
it
> realizes an (M,R)-system. my argument would still hold. This
is because of the indefinite article
> “an” that Bob used. This
statement of Q3' would still mean that if C is
> a cell, then THERE
EXISTS an (M,R)-system S such that C realizes S. And
> if THERE
EXISTS an (M,R)-system S such that C realizes S, then C is a
>
cell. It STILL does NOT mean that if one comes up with an arbitrary
> (M,R)-system, there has to be a cell that realizes it. See how
crafty
> Bob was in his use of the language!
>
> So it
would not “collapse” Bob’s theory even if somebody comes up with
> an
(M,R)-system that no cell can realize.
> The nature of a “necessity
> statement” is that the
better the necessary condition (in characterizing
> a property, in this
case “life”), the smaller the complementary set
> (i.e. things that do
not have the property, in this case “not life”); in
> other words, the
closer the condition to being sufficient. I felt that
> the
condition “closed to efficient causation” is so close the being
>
sufficient that one may as well ACCEPT, or BELIEVE, that it is so. Or,
> MAKE IT SO (quoting Jean-Luc Picard), as it were. I believe
that was
> what Bob did in Q1.
>
> One must also
understand that the “if, and only if” phrase is what
> mathematicians
use when they DEFINE something. So we can take that Q1
> is Bob’s
DEFINITION OF LIFE. The “only if” part provides what is
> needed,
and the “if” part tightens the complementary set.
>
> Q2, then,
is not so much a retraction, as it is an explanation. It is
>
Bob’s Godelian suggestions that perhaps the sufficient conditions for
>
life are undecidable.
>
> Immediately following Q3, we have this
sentence:
>
> Q4. Conversely, I see no grounds for refusing
to call such a
> realization an autonomous life from, whatever its
material basis may be.
> (p.263 of “Essays on Life Itself”,
Section on The (M,R)-Systems)
>
> This is the sufficiency part of
Q3. But note that Bob used “I see no
> grounds for
refusing”. This is not a mathematical proof. This is a
>
statement of BELIEF (dare I say FAITH). This is a “Make it so!”
>
> Aloisius
> --
> Dr. Aloisius H. Louie
>
***>
>