[Date Prev][Date Next][Thread Prev][Thread Next]   [Date Index] [Thread Index] [Author Index

Re: Could you give me your analysis of this?



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
 
 
 
-----Original Message-----
From: ROSEN Forum [mailto:***On Behalf Of Judith Rosen
Sent: Friday, September 10, 2004 11:01 PM
To: ***
Subject: Fw: Could you give me your analysis of this?

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
> ***
>
>