Seven.
I made major advances in my conceptual understanding of the W(y) model yesterday, to the point that I used it as a point of joy to keep me happy while watching the Eagles game. Anyway, now that the conceptual barrier that yesterday’s work knocked down, I am now understanding math at a new level of abstractness. Once a process becomes an object. That’s the sign of having a concept completely clarified. Being able to USE the mathematical structure. Its a great feeling, although somewhat rare.
I am turning back to those writings on Dimensional Analysis (Bridgman, 1921, Barenblatt, 2003, Hornung, 2006). This is the “conceptual scheme” that I have to clarify for everyone.
Purpose: Why am I writing about Dimensional Analysis?
Dimensional analysis underpins Harrison White’s W(y) Model, but this style of reasoning is very rarely taught in the sociology. Dimensional analysis has high academic credentials– it is the theoretical underpinning of much of the studies of turbulence– aeronautics, and other such applied engineering physics. This is not a trendy, faddish subject–it has been a central component of the physics “mentality” for almost a century if not longer. (Bridgman, 1921 is still considered a central work) A more realistic version of strategic action, based on “condensed-matter” or “few-body” principles could use the skills developed in these fields to develop better models of of how social action occurs within groups extending beyond the dyad, but smaller than the amorphous crowd. Patterns of interaction amongst social actors/players in the range of 5-10 members.
We will be Wittgensteinians here– rather than defining what “dimensional analysis” is, I would rather give examples of the types of problems that dimensional analysis deals with. My sources are Hornung and Barenblatt, who both work in the field of fluid dynamics. (at Cal-Tech and Cambridge, respectively)
This is Barenblatt’s work:
http://www.amazon.com/gp/reader/0521533945/ref=sib_dp_ptu#reader-link
“Scaling” is the title of the book, and it is the style of “qualitative” mathematical analysis that I have always enjoyed immensely. (Polya, 1954, Martin Gardner, Hofstadter, 1979, Davis & Hersh, 1983, Feynman, 1983, Borges, Nabakov, and large numbers of others) This is the style of mathematical reasoning that will be used more in the future, since there have been recent drastic advances in the interactivity between the person and the computer that allow us to exploit our spatial intuiton in more dimensions more readily.
I am typing out the table of contents for references:
Introduction
Chapter 1. Dimensional Analysis and Physical Similarity
1.1 Dimensions
1.2 Dimensional Analysis
1.3 Physical Similarity
Chapter 2. Self-similarity and Intermediate Asymptotics
Chapter 3. Scaling laws and self-similar solutions that cannot be Obtained by Dimensional Analysis
Chapter 4. Complete and incomplete similarity. Self-similar solutions of the first and second kind.
Chapter 5. Scaling and transformation groups. Renormalization group.
Chapter 6. Self-Similar Phenomena and Traveling Waves
Chapter 7. Scaling Laws and Fractals
Chapter 8. Scaling Laws for Turbulent well-bounded shear flows at very large Reynolds numbers
If you are trying to understand phenomena that operate at multiple scales, then it seems that this line of research is the way to go. This is basically my rationale for wanting to learn this field. Is this justifcation enough? So far so good. Also, I could seriously see myself working for a good long time working on this stuff. I could even see myself teaching this stuff on the side. Its close to the scientific aesthetic I am trying to capture. It is more of an MIT style than what we usually see in Sociology. But I have to be around those types of ideas in whatever I end up doing. (A boat I missed at Haverford — the non-linear physics stuff.)
So a glance at the Table of Contents shows us that some of the “key words” associated with Dimensional Analysis are:
DIMENSION
PHYSICAL SIMILARITY
SELF-SIMILARITY
INTERMEDIATE ASYMPTOTICS
COMPLETE AND INCOMPLETE SIMILARITY
TRANSFORMATION GROUPS
RENORMALIZATION GROUP
SELF-SIMILAR PHENOMENA AND TRAVELING WAVES
SCALING LAWS AND FRACTALS
TURBULENCE
SHEAR FLOWS
REYNOLDS NUMBER
Many of these themes are directly related to our work on turbulence, extreme events, non-equilibrium dynamics, non-linear systems, etc. So why not use the tools made by the best scientists working in these fields, since they directly involve the types of processes that we are interested in?
Barenblatt begins his work:
“Applied mathematics is the ART of constructing mathematical models of phenomena in nature, engineering and society.” Every model is based on a certain “IDEALIZATION” of the “PHENOMENON”. The model is not the phenomenon itself, but an approximation of that phenomenon. This is one of the useful pieces of information to know when thinking about modeling in the sciences. Whenever you make a mathematical representation of a situation in the real world, you are by necessity providing a description that has less information than what is being copied. For instance, a truly “accurate” map of a region would be as large as the map itself. So a situation can be understood at multiple levels of “focus” that each are somehow all true, and that cohere together. There is of course no “God’s eye” view, and that is the challenge that physics has been dealing with for the past 100 years (usually attributed to the rise of General Relativity and Quantum Mechanics at the turn of the 20th century).
The social sciences have dealt in many of these issues of observer-dependence, interaction effects, and so on, in both the “qualitative” and “quantitative” branches of sociology in various guises. (It is staggering the amount of literature there is on interaction effects, across the political spectrum, etc. and across the social sciences.) The approach of Barenblatt’s “applied mathematician” is half-way between the two versions of researchers. On the one hand, the applied mathematician uses numbers and counts things, and is thus “quantiative” in this sense. On the other hand, the applied mathematician draws upon his or her store of mathematical techniques and knowledge (we could call it a cultural “toolkit”) to create mathematical representations of particular phenomena, real or ideal. This is the ART that Barenblatt refers to above, and there is no one single method of calculating this aspect of mathematical practice.

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