More on Nonlinearity and Mechanistic Explanation

The point is that the more localizability and decomposition fail, the harder mechanistic explanation will be, and a high degree of nonlinearity is bad news for both of these (C&S, 2008, p. 16).

Ok.  So, how is nonlinearity make localizability and decomposition harder?  I guess that if you can't decompose a system into parts, then maybe by the MDC and Bechtel definitions you can't have mechanistic explanation, so why does nonlinearity make composition harder?

(And really, decomposition could be harder with nonlinearity, but if it is still possible wouldn't that be enough to remove the block on mechanistic explanation?)

Nonlinearity and Mechanistic Explanation

So, nonlinearity is supposed to block mechanistic explanation:

A linear system can be decomposed into subsystems. Such decomposition fails however in the case of nonlinear systems. When the behaviors of the constituents of a system are highly coherent and correlated, the system cannot be treated even approximately as a collection of uncoupled individual parts. Instead, some particular global or nonlocal description is required, taking into account that individual constituents cannot be fully characterized without reference to larger scale structures of the system such as order parameters. (Chemero & Silberstein, 2008, p. 16).

But, why does decomposition fail in the case of nonlinear systems?  Think of a double pendulum.  Why can that not be decomposed into two pendulums?

It is not a part of mechanistic explanation that one treat systems as "a collection of uncoupled individual parts" if in fact they are a collection nonlinearly coupled parts. Rather, I would think that mechanistic explanations of systems of nonlinearly coupled components should involve treating them as systems of nonlinearly coupled components.  I know that it is common to think that nonlinearity causes explanatory problems, but it can't be that nonlinearity forces us to treat such systems as collections of uncoupled individual parts.

Moreover, in either the linear or the nonlinear cases, the MDC approach (and I think the Bechtel approach) to mechanistic explanation invokes higher level descriptions (global descriptions) which would be the things to be explained by the lower level mechanisms.  So, there is no "instead" about particular global or nonlocal descriptions.

Nor, need the mechanist "fully characterize" the individual constituents without reference to larger structure of the system.  Isn't that what "fully characterize" means one does?  Refer to the larger structure?

To repeat, however, I think there could be something problematic about nonlinear systems, but I don't see that C&S have put their finger on it.

So, Why Isn't the Methodology of Co-ordination Dynamics an Instance of Mechanistic Explanation?

The methodology of coordination dynamics is as follows. First, for the system as a whole, discover the key coordination variables and the dynamical equations of motion that best describes how coordination patterns change over time. Second, identify the individual coordinated elements (such as neurons, organs, clapping hands, pendulums, cars, birds, bees, fish, etc.) and discern their dynamics. As Kelso and Ensgtrom say, this is nontrivial because the individual coordinated elements are often themselves quite complex, and are often dependent upon the larger coordinated system of which they are components (2006, 109). They put the point even more strongly, “in the complex systems of coordination dynamics, there are no purely context-independent parts from which to derive a context-independent coordinative whole” (2006, 202). Third, derive the systemic dynamics from the description of the nonlinear coupling among the elements. It is this nonlinear coupling between elements that allows one to determine connections across different levels of description. It is important to note that, as in all dynamical explanation, discovering both the systemic dynamics and that of their component parts requires specifying boundary conditions that “establish the context for particular behaviors to arise” (Kelso and Engstrom 2006, 109). The behavior of the whole system ‘emerges’ from the nonlinear interactions among the elements of the system in a particular context where the elements and the contextual features are coupled and mutually codependent. The individual coordinating elements form a collective whole in the sense that microscopic degrees of freedom are reduced to a much smaller set of context dependent coordination variables or order parameters that greatly constrain the behavior of the elements. (Chemero & Silberstein, 2008, pp. 12-13).

So, if we understand C&S's "elements" as entities and their "dynamics" as the interactions among the entities, it looks like we are pretty far along the path to, say, the Machamer, Darden, Craver theory of mechanistic explanation in terms of entities and their activities.  So, why isn't the methodology of co-ordination dynamics an instance of mechanistic explanation?  I figure there could be an answer, but the contrast between mechanistic explanation and whatever rival C&S are offering does not seem to be all that stark.  And, what exactly is it?

Bechtel might not like this (cf., C&S, 2008, p. 16), but what reason is there?  For further comment on this, tune in tomorrow.

Irreducible Brain Components Leads to Cognitive Extension?

C&S write,

If it turns out that there are irreducible mechanisms (nonlocalizable or nondecomposable) at the highest levels within the brain then, because it is at roughly the same scale and there are many interactions at that shared level, it may be necessary to bring in the external environment as part of the cognitive mechanisms in question or at least as essential background for their function. (Chemero & Silberstein, 2008, p. 8).

I'm not getting the thinking here.  So, suppose there are some irreducible (cognitive?) mechanisms at the highest levels in the brain.  Why would this make it necessary to bring in the external environment as part of the cognitive mechanisms in question?  I'm not getting it.  C&S do hedge and throw in "it may be necessary", but still why may this be necessary?

There are other considerations given later, such as that mechanisms often function only in certain contexts, but this is a separate matter from the irreducibility consideration cited above.

Those Successful Skinnerians and Gibsonians

C&S write,

Both Skinnerians and Gibsonians have been very successful as psychologists, and both groups have achieved results that are undeniable psychological milestones. So these views are neither nonstarters, nor obviously crazy.  (Chemero & Silberstein, 2008, pp. 4-5).

This seems to me a bit simplistic.

For one thing, recall that the Ptolemaic astronomers were very successful as astronomers and had results that are undeniable astronomical milestones, but much of their theory was wrong.  So, one can still achieve results with a flawed theory.

For another, I think that one has to recognize that theories have different parts (to speak generically).  Some parts might be true and others false.  So, maybe it is true that the world contains affordances, but false that these are directly perceived.  Indeed, one philosophical sort of project might be to draw distinctions among the components of theories to see how evidence supports one or another of them. 

For a third, I wouldn't want to undertake the burden of proof to show that Skinnerian or Gibsonian psychology is a nonstarter or obviously crazy.  (Maybe just crazy?)  Maybe just wrong on certain important points.

Psychology without the brain?

Chemero and Silberstein report that:

Note that neither Gibson nor Skinnerians claim that the brain is not importantly involved in cognition; rather they claim that psychologists can do all their explanatory work without referring to the brain.  (Chemero & Silberstein, 2008, p.4).

Ok. So, what is the story about why John Dalton was color blind?  He lacked a type of retinal cone, right?  So, do Gibson and Skinner dodge this objection by saying that the retina is not part of the brain?  Or by saying that color blindness is not a concern of psychology?

It seems to me not enough to say the retina is involved in color vision.  It looks like facts about the retina do some explanatory work.

This sort of line looks to have it both ways, that the brain is, of course, important, but not important.

Another Instance of the C-C Fallacy?

Here Chemero and Silberstein seem to me to attribute the C-C fallacy to Clark:

Clark (2003) takes this further, arguing that external tools (including phones, computers, language, etc.) are so crucial to human cognition that we are literally cyborgs, partly constituted by technologies (Chemero & Silberstein, 2008, p. 5).

The fallacy here is in thinking that something that contributes "crucially" to some sort of cognitive or behavioral success is thereby cognitive.  The crux of the difference between what Rupert calls HEC and HEMC is the difference between crucial causal contributors being cognitive crucial causal contributors and non-cognitive crucial causal contributors.

Future Posts 6/17/2010

I'm reading Chemero & Silberstein's "After the Philosophy of Mind: Replacing Scholasticism with Science", available here, and will be posting my typical "reading notes" in a few days.

The "EC = Science, Anti-EC = a priori speculation" meme 3

Here are Chemero and Michael Silberstein on this meme:

the extended cognition thesis might really be true. The holism question is an open and empirical one—the reason to attempt full-blooded extended cognitive science is that the world might really be that way and such methods may capture that. Such questions cannot be settled a priori by any kind of essentialist arguments about what is and what is not a cognitive system. (Chemero & Silberstein, 2008, p. 132.)