[FRIAM] Societal collapse

[Jochen Fromm]

Here is another interesting Nature linkhttps://www.nature.com/news/the-greatest-vanishing-act-in-prehistoric-america-1.18700  The collapse of civilizations is a fascinating phenomenon, from the abandoned pueblo dwellings in the Mesa Verde National Park to the remains of the Minoan culture on Crete.Would you like to present parts of your work on Friday? Maybe you have an old PowerPoint presentation that you can show us via Zoom? -J.
-------- Original message --------From: Steve Smith <sasmyth at swcp.com> Date: 6/23/20  23:25  (GMT+01:00) To: friam at redfish.com Subject: Re: [FRIAM] Societal collapse 
    J -
    
      
      Is it possible to create agent-based models of
        societal collapse? This Nature article argues human societies
        have mind- boggling complexity, but I am not so sure if it is
        impossible. 
      
    
    I appreciate the link to the Nature article... I particularly liked
    the caution about misuse of the "Retrospectoscope" , and the
    reference to Hari Seldon and PsychoHistory.   "... societal spasms
    are cyclic" seems nearly tautological, but a good reminder.    I
    appreciate that many are now treating global
    socio-economic-political systems (coupled with the earth-systems) as
    a truly complex system as best they can.
    Of course it is possible to build an ABM in this domain...  bit
      as the article gestures toward, there is no bottom to the possible
      complexity (at least down to Glen's previous reminders to us that
      our individual microbiome is a key part of our "selves" in more
      ways than simply accounting for body mass or cell count). 
    
    Unfortunately we aren't just dealing with the risk of our
      multiple (highly coupled, but nevertheless diverse) facets of
      societies and whole societies collapsing and taking one another
      down like dominoes (or a house of cards),  but the earth-systems
      our high-tech, energy-and-minerals-and-plant-products-hungry 
      society depends on being able to draw from (exploit?).   
    
    We looked at an SEIR/ABM covid-model for NM at the individual
      level which seemed (barely) tractable on a single machine (memory
      size)...    I have worked with Systems Dynamics models which are
      highly aggregative and we even ran 100,000 samples from the World3
      model from 1900-2100 as a test/demonstration last year.   The
      World3 model focuses on Economics and Resource Utilization and was
      conceived around the idea of "Limits to Growth"...  it doesn't
      really do justice to more subtle societal issues (like social
      justice, massive political shifts, personal violence, etc.)  
      Within the 10^5 parameter sweep we started with there are
      (naturally) large subregions where human life becomes acutely
      miserable.   There are lots of criticisms of the model and it IS
      very long of tooth. 
    
      I'd be interested if anyone knows of ABMs or Discrete Event
      Simulations that aspire to study more than the smallest of
      subsets.  
    
    Our experiments with World3 were as much about studying high
      dimensional ensemble-problem sets where intuition can be used to
      double-check the results, as it was about the problem domain of
      impending collapse.
    
    
    This 2D projection of a 3D "projection" based on
      an 11D Self Organizing Map (SOM) was our "best shot" at analyzing
      this 100k ensemble.   Without stereography or motion parallax, the
      3D structure is probably hard to see... it *may* be evident that
      one of the most notable features is "continuity" that this appears
      to be a complex 2D surface "folded" into 3D.   The 2D continuity
      is at least partly a direct artifact of our choice of SOM focused
      on preserving local distances.   The coloring is on a red-blue
      spectrum with human population encoding population (ending
      population 2100).  One of the surprising artifacts found in this
      rendering is the relatively regular distribution of high/low
      population peppered through the otherwise dominantly low/high
      regions.   An obvious "positive" correlation between "good
      results" and "populations" shows that the sooner we have a
      population collapse, the better the chance that the remaining
      population will enjoy a high quality of life (by some measure).   
      We have many hypotheses to test on this rendering, such as whether
      the "1D edges" of the embedded surface represent interesting (and
      relevant to the problem not our choice of encoding) samples.   One
      partial result is that (within our sampling) these extrema don't
      have any of the "contrary" samples (high among low or
      vice-versa)....
    
    
    
     This work is temporarily on hold, but the same
      methods are being explored on other problem sets (where there is
      funding)...  
    
    
    
    The main point of this example is that complex
      models yield highly complex results and it is not always obvious
      or easy to decide what the truly interesting "trade space" is, and
      whether or not there are interesting parts of these
      high-dimensional landscapes that allow for some  useful
      intuition.  
    
    
    
    - Steve
    
  
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