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    <title>Notebooks   </title>
    <link>http://bactra.org/notebooks</link>
    <description>Cosma's Notebooks</description>
    <language>en</language>

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    <title>Biological Order, or Levels of Organization</title>
    <link>http://bactra.org/notebooks/1998/10/11#biological-order</link>
    <description>

&lt;P&gt;The whole notion that living things are organized in hierarchical levels
(monomers inside macromolecules inside membranes inside organelles inside cells
inside organs inside organisms) seems to have been thrust upon a willing world
in the '20s and '30s by people like &lt;a href=&quot;needham.html&quot;&gt;Joseph Needham&lt;/a&gt;
(his &lt;cite&gt;Order and Life&lt;/cite&gt; is a really classic exposition) and Waddington
and Woodger (qv. below).  This is now a thoroughly received notion, the sort of
thing diagramed in high school biology texts, usually with a pair of arrows,
one pointing up to show new properties &lt;a
href=&quot;emergent-properties.html&quot;&gt;emerging&lt;/a&gt;, and another pointing down to show
components constrained by the level above (&quot;downward causation&quot;); &quot;and another
going nowhere at all just for show.&quot;

&lt;P&gt;Probably it's pretty much correct, but I can't help thinking it's much too
pat.  Where, for instance, do bones fit in this?  Or the endocrine system?
Furthermore downward causation seems suspect to me.  I'd be much more
comfortable with &lt;em&gt;lateral&lt;/em&gt; causation: the component molecules of (say) a
membrance are constrained, yes, but by each other.

&lt;P&gt;Suppose that instead of looking at spatial encapsulation, at what is inside
what, we looked at causal isolation, so that item A in the hierarchy includes
lower-level items B, C, D if B, C and D interact more strongly with each other
than with the outside world, and this is no longer true is we remove any one of
the three, or add a fourth.  I think this comes closer to &quot;dividing according
to the natural formation, where the joint is, not breaking any part as a bad
carver might&quot; (Plato); in fact it seems to me that the spatial hierarchy
always makes some kind of implicit appeal to autonomy to rule out arbitrary
boundaries, which would say include half the liver, and a little bit of the
left lung as well.  (But the new scheme allows for such oddly shaped items, if
their parts are strongly connected.)  Furthermore, the causal version can be
extended to machines, or societies of organisms, with less hand-waving and
grimacing.  --- This idea comes from thinking about &lt;a
href=&quot;christopher-alexander.html&quot;&gt;Christopher Alexander&lt;/a&gt;'s &lt;cite&gt;Notes on the
Synthesis of Form,&lt;/cite&gt; where drives home the point that, if you want to
break a problem up into solvable pieces, spatial proximity is much less useful
than causal links.  (I'm agnostic about his specific algorithm for carving at
the joints, and I think he's come to feel the same way.)

&lt;P&gt;Now: does this give us any sort of handle on &lt;a
href=&quot;self-organization.html&quot;&gt;self-organization&lt;/a&gt; in general?  It's easy to
say, &quot;Yes, if a new level of the hierarchy forms, that it self-organization,&quot;
and there are cases where this seems to fit: spiral waves, say, or the more
common objects in Life, are spatially well-defined and relatively autonomous.
(In the lab, do we ever see any sort of pattern of spiral waves?)  However,
	&lt;ol&gt;
	&lt;li&gt; How can you tell when this happens?
 	&lt;li&gt; Is self-organization &lt;em&gt;always&lt;/em&gt; the same as a new level of the
hierarchy?
	&lt;li&gt; Is there in fact only one hierarchy?
	&lt;/ol&gt;

If anything, I'd guess that the reverse is true, that getting a good handle
on self-organization would let us put some spine into these ideas of
biological order; but maybe that's just my physicist's hubris speaking
again.

&lt;ul&gt;See:
	&lt;li&gt;Walter Fontana and Leo W. Buss, &quot; `The Arrival of the Fitest':
Towards a Theory of Biological Organization,&quot; &lt;cite&gt;Bulletin of Mathematical
Biology&lt;/cite&gt; &lt;strong&gt;56&lt;/strong&gt; (1994): 1--64
[&lt;a href=&quot;http://www.santafe.edu/~walter/publications.html&quot;&gt;online&lt;/a&gt;]
	&lt;li&gt;Joseph Needham, &lt;cite&gt;Order and Life&lt;/cite&gt;
	&lt;li&gt;A. R. Peacocke, &lt;cite&gt;An Introduction to the Physical Chemistry of
Biological Organization&lt;/cite&gt; [Lots of physical chemistry, little biological
organization]
	&lt;/ul&gt;

&lt;ul&gt;To read:
	&lt;li&gt;Henri Atlan, &lt;cite&gt;L'organisation biologique et la theorie de
l'information&lt;/cite&gt; [Surely this must have been translated?]
	&lt;li&gt;E. Bienenstock, F. Fogelman Soulie, G. Weisbuch (eds.),
&lt;cite&gt;Disordered Systems and Biological Organization&lt;/cite&gt;
	&lt;li&gt;Peter Dittrich and Pietro Speroni di Fenizio, &quot;Chemical
organization theory: towards a theory of constructive dynamical systems&quot;, &lt;a
href=&quot;http://arxiv.org/abs/q-bio.MN/0501016&quot;&gt;q-bio.MN/0501016&lt;/a&gt;
	&lt;li&gt;Andre Lwoff, &lt;cite&gt;Biological Order&lt;/cite&gt;
	&lt;li&gt;Ron Maimon, &quot;Computational Theory of Biological Function I&quot;,
&lt;a href=&quot;http://arxiv.org/abs/q-bio.MN/0503028&quot;&gt;q-bio.MN/0503028&lt;/a&gt;
	&lt;li&gt;Jay E. Mittenthal, Arthur B. Baskin (eds.) &lt;cite&gt;Principles of
Organization in Organisms&lt;/cite&gt;
	&lt;li&gt;Harold J. Morowitz, &lt;cite&gt;Energy Flow in Biology; Biological
Organization as a Problem in Thermal Physics&lt;/cite&gt;
	&lt;li&gt;Susan Oyama, &lt;cite&gt;The Ontogeny of Information&lt;/cite&gt;
	&lt;li&gt;Henry Quastler
		&lt;ul&gt;
		&lt;li&gt;&lt;cite&gt;The Emergence of Biological Organization&lt;/cite&gt;
		&lt;li&gt;(ed.), &lt;cite&gt;Essays on the Use of Information Theory in
Biology&lt;/cite&gt;
		&lt;/ul&gt;
	 &lt;li&gt;J. H. Woodger
		&lt;ul&gt;
		&lt;li&gt;&lt;cite&gt;Axiomatic Method in Biology&lt;/cite&gt; [Attempt to
apply the methods of &lt;a href=&quot;mathematical-logic.html&quot;&gt;mathematical logic&lt;/a&gt;
to biology, c. 1937; &quot;with appendices by Alfred Tarski&quot;.  Unfortunately he
takes &quot;organized system&quot; as a primitive term...]
		&lt;li&gt;&lt;cite&gt;Biological Principles: a Critical Study&lt;/cite&gt;
		&lt;/ul&gt;
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