This post is Part 2 on Terrence
Deacon’s Incomplete Nature (see here for Part 1). I’m now ten chapters in. The prose is still dense and
repetitive, but I enjoy encountering interesting nuggets amidst the windy
narrative. Deacon is also building up his case by introducing different levels
of dynamics and making analogies to Aristotle’s Four Causes.
For most physical scientists,
Aristotle’s efficient cause is our main focus, the process by which some
physical interaction takes place. As a chemist, I’m also interested in the
material cause: the identities of the molecular structures that are involved in
these interactions. We chemists often think of these two causes in terms of the
words ‘function’ and ‘structure’ respectively. The distinction is not always clear-cut.
Deacon begins Chapter 6 by
discussing constraints. This, I think, is a very important feature. He exhorts
his readers to think about what is absent
when a constraint is in place, i.e., something couldn’t happen (which otherwise
could have) if the constraint wasn’t there. It might seem odd to try and
describe something by what it is not, but this is a time-honored practice that
is simply practical when trying to describe seeming simple all-encompassing
things: Energy, Life, God, and as mentioned in my previous post: Emergence.
This leads us to statistical
thermodynamics – a course I regularly teach that students find painful. The
beauty of statistical thermodynamics is that in a closed system (i.e., one with
certain constraints), you don’t have to keep track of the individual movements
and interactions of millions or zillions or moles of molecules. With the help
of first-year college calculus, you can actually describe macroscale
thermodynamic properties (that you can also measure experimentally) as averages
of a zillion motions that are surprisingly easy to calculate. (At least they’re
easy to calculate in idealized system, but there are many tricks one can use to
handle non-idealized ‘real’ systems.)
Deacon argues that “where
constraints at a higher level are linear extrapolations of those at a lower
level… there is no loss due to reductive analysis. But where there is
non-linear constraint… both physical and analytical decomposition eliminate the
source of this constraint, and hence the source of its causal power. Such cases
should therefore be paradigm examples of emergent transitions.” Essentially
Deacon is saying that equilibrium thermodynamics is subject to reductive
analysis – explaining a macroscopic property in terms of its tinier components –
because of the linearity in constraint extrapolation. But this strategy of
reductionism fails in emergent systems because it throws out the baby with the
bath water.
Deacon’s dynamics paradigm has
three levels: homeodynamics, morphodynamics, teleodynamics. Each ‘higher’ level
is supervenient on its lower levels. Homeodynamics, the lowest level, is akin
to equilibrium statistical thermodynamics. There is a tendency to reduce any
asymmetries, i.e, the closed system will try to degrade any gradients that are
present. Is there a difference that makes a difference? Get rid of it!
Level the playing field! Equality for all!
There’s a nice nugget as Deacon
discusses how Energy entered the lexicon, as introduced by the polymath Thomas
Young in 1807. The Greek energia
combines a prefix meaning ‘in’ or ‘to’ with a root word meaning ‘activity’ or ‘work’.
In that sense, whenever my students define energy as the “ability to do work”,
they’re not far wrong – but it’s superficial at best since we don’t really know
what energy is. Deacon says: “… it might be more accurate to say that the
capacity to do work is a gradient
across which there is a tendency to even out and dissipate. Energy is more
accurately, then, a relationship of difference or asymmetry, embodied in some
substrate, and which is spontaneously unstable and self-eliminating… I suggest
that the key to understanding what
energy is is to stop focusing on the stuff that embodies it, and instead
consider the form that is embodied…
energy is a relationship of difference that tends to eliminate itself.” That’s
the second law of thermodynamics in a nutshell and Deacon will attempt to
connect this concept with Aristotle’s formal
cause.
One has to slog through Deacon’s
definitions of orthograde (with the
gradient, go with the flow!) and contragrade
(against the flow), but he needs these to set up his next level:
morphodynamics. His essential argument is that the interplay of orthograde and contragrade
processes at one level has an effect on constraints, and thereby allows (in the
vicinity of an attractor) the
emergence of supervenient levels. What is morphodynamics? In a nutshell, it has
to do with the behavior of non-equilibrium thermodynamics and open systems. The
Benard cell is Deacon’s prime example. Nothing new here. But he does have an
easy to picture analogy of a building that’s hotter inside than outside, and
how opening certain windows or doors removes a constraint for dissipating heat
and can introduce new dynamical flows. But the winds could cause a door to slam
shut thus adding a new constraint, and so on.
But apparently this is not
enough, and there needs to be another supervenient level. The orthograde and
contragrade at the morphodynamics level allow the emergence of teleodynamics.
You can sense Aristotle’s final cause lurking here. Deacon has a nice little
chart that distinguishes the three. I’ve put them in the bullet points below.
·
Homeodynamics
(e.g. thermodynamics): the orthograde is an increase in entropy, the removal of
constraints, and moves towards equilibrium
·
Morphodynamics
(e.g., self-organization): the orthograde is an amplification of constraints
leading to dynamical regularization and metastability
·
Teleodynamics
(e.g.
life): the orthograde is reproduction and repair of systems, i.e., preserving
constraints and allowing them to correlate
Honestly, I’m not sure why there aren’t more levels. It
could just as well be turtles all the way up. Autocatalysis and self-assembly
are thrown together to make something that is sorta like life, but not quite. A
negentropy ratchet is thrown in. You can tell that I’m finding this all to be
obfuscating rather than clarifying. Deacon seems to promise that we’ll get to
some useful examples, but I’ve yet to see them. But I’m hoping Chapter 11 (“Work”)
will tie some of these threads together. That’s my work for tomorrow morning!