Difference Dynamics

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!