>Also, even if it were possible for a
>machine to be able to (from a large bin of parts) construct an exact
>copy of itself, it wouldnt be self-producing.
>
> Self-producing, as I understand it, means that every part of
>a system is continually being turned over. The material that makes
>up an identifiable part was manufactured (or processed) by the
>system itself.
That viewpoint may be a little too broad. Certainly, from the
elemental/atomic level, the parts are not produced by the system itself. And
humans cannot survive on pure elements, our diet requiring many complex
molecules typically found in other organic life (proteins, carbohydrates,
enzymes)... Some parts are not normally recycled or replaced- bone, teeth,
brain cells, DNA...
So the point that machines are made up of externally-produced parts and
living things made of internally-produced parts might be better modified to
say that the difference is in the utilization of 'parts' (regardless of
origin). We would then check whether the utilization of parts was
internally or externally directed. This might avoid classifying the
recipient of an artificial heart as a "machine".
But then what degree of autonomy for such direction qualifies as
"autopoietic"?
I confess some frustration that it seems that artificially created
"autopoiesis" is possible, while my intuition tells me that something big is
missing here...
In a message dated 95-08-20 19:14:58 EDT, Onar wrote:
>
>I like the comparison between inanimate machines and living machines (if I
>may
>call them so). When studied purely as i/o systems they are very similar. The
>great difference, as I see it, is that the "machinery" of the cell is
largely
>self-organized.
I understand Rosen in LIFE ITSELF to make the point that living systems are
fully self-organized, vs. an artifact that has externally-imposed
organization. However, there is an infinite(or at least 'vast') regress of
causes for biologic organisms. How can any one be "closed to efficient
causation"? Or similarly, how can an organism be fully self-producing when
each half of its genetic code sprang fully formed from its parents during
meiosis(speaking for those of us who are sexual productions)?
So I would agree with Onar that "largely self-organized" may be the better
description. But this seems to eliminate "self-organization" as a
distinguishing feature that is present only in living things.
Then we return to the additional measure mentioned by Onar- "dissipation".
This term may have developed a specific meaning within these posts, but I
understand a dissipative structure (per I.Prigogine) as one which maintains a
low entropy (ordered) state through conversion of low entropy
items(high-frequency sunlight, protein, etc.) from its environment into
higher-entropy items (radiated heat, etc). This is the central feature of a
metabolic process.
But not all metabolic/dissipative systems are in continuous use. Dormant
bacteria and viruses don't appear to 'metabolize' or 'dissipate'. Do dry
seeds? Should we consider them alive?
Mike