Wedtech to Friam: earthquakes
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Dear All,
We have been having a discussion on a SF Site called Wedtech about the relationship between explanation, simulation, and prediction. If you want to get a sense of the starting point of that discussion, have a look at Josh Epstein's forum entry in the current JASSS, which seems to be just about as wrong headed as a piece of writing can be. In it, he makes a radical separation between prediction and explanation, implying that the quality, accuracy, scope, and precision of predictions that arise from an explanation is no measure of that explanation's value.
In the course of trying to discover where such a silly idea might have come from, I was led to literatures in economics and geophysics where, indeed, the word "prediction" has taken on a negative tone. These seem to be both fields in which the need for knowledge about the future has overwhelmed people's need to understand the phenomenon, so that predictive activities have way outrun theory.
However, acknowledging the problem in these literatures is not the same thing as making a principled claim that prediction has nothing to do with explanation.
In the course of thinking about these matters, I have stumbled on an extraordinary website packed with simulations done by people at the USGS in Menlo Park California. the page is http://quake.usgs.gov/research/deformation/modeling/animations/. I commend to you particularly, the simulations done on teh Anatolian Fault in Turkey (BELOW the stuff on california) and ask you to ponder whether the mix of simulatoin, explanation, and predicition is appropriate here. I suggest you start at the top of the Anatolian series and move from simulation to simulation using the link provided at the bottom right of each simulation. Stress buildup and stress release are represented by red and blue colors respectively and the theory is one of stress propogation. I would love to know where the colors come from i.e., how stress is measured. If there is no independent measure of stress, then, as in psychology, the notion of stress is just covert adhockery.
Please let me (us) know what you think.
Nick
Nicholas S. Thompson
Emeritus Professor of Psychology and Ethology,
Clark University ([hidden email])
============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
Re: Wedtech to Friam: earthquakes
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Hi Nick - yes there's an independent measure of stress. It involves structural geologists going out into the field and measuring dips, inclines, deformations etc.. See http://en.wikipedia.org/wiki/Structural_geology for links.
Robert
On Mon, Dec 1, 2008 at 1:03 PM, Nicholas Thompson <[hidden email]> wrote:
============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
Re: Wedtech to Friam: earthquakes
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In reply to this post by Nick Thompson
There’s always the difference between the kind of question
you ask and the type of prediction and explanation for it.
For example, you might ask either “what generally happens here” or “what
is happening here”. The first asks for a simple explanation and
a rule of thumb type prediction. It might be helpful for responding
to the second question, or not. The second question is more
about individual complex systems in a particular circumstance requiring one to
start from the limited information that raises the question and to go to the
trouble of expanding your understanding while exploring possible patterns in
the environment until you find one that seems to fit. I think there are lots of differences between any kind of explanatory
causation and the instrumental causes. Maybe explanations become
useless if they try to include all the complexity of the instrumental processes,
but also often loose their value by ignoring the underlying complexity too. Re: earth quakes, I went to a lecture at Columbia recently that
was just great on the physics of ‘slow slips’ in a shearing crust, large
horizontal zones of gradual internal tearing within the crust, having leading vibration
events and propagation fronts, etc. Phil Henshaw From:
[hidden email] [mailto:[hidden email]] On Behalf Of Nicholas
Thompson Dear
All, We
have been having a discussion on a SF Site called Wedtech about the
relationship between explanation, simulation, and prediction. If you want
to get a sense of the starting point of that discussion, have a look at Josh
Epstein's forum entry in the current JASSS, which seems to be just about as
wrong headed as a piece of writing can be. In it, he makes a radical
separation between prediction and explanation, implying that the quality,
accuracy, scope, and precision of predictions that arise from an explanation is
no measure of that explanation's value. In
the course of trying to discover where such a silly idea might have come from,
I was led to literatures in economics and geophysics where, indeed, the word
"prediction" has taken on a negative tone. These seem to be
both fields in which the need for knowledge about the future has overwhelmed
people's need to understand the phenomenon, so that predictive activities have
way outrun theory. However,
acknowledging the problem in these literatures is not the same thing as
making a principled claim that prediction has nothing to do with
explanation. In
the course of thinking about these matters, I have stumbled on an extraordinary
website packed with simulations done by people at the USGS in Menlo Park
California. the page is http://quake.usgs.gov/research/deformation/modeling/animations/.
I commend to you particularly, the simulations done on teh Anatolian Fault in
Turkey (BELOW the stuff on california) and ask you to ponder whether the
mix of simulatoin, explanation, and predicition is appropriate here. I
suggest you start at the top of the Anatolian series and move from simulation
to simulation using the link provided at the bottom right of each
simulation. Stress buildup and stress release are represented by red and
blue colors respectively and the theory is one of stress
propogation. I would love to know where the colors come from i.e.,
how stress is measured. If there is no independent measure of stress,
then, as in psychology, the notion of stress is just covert adhockery. Please
let me (us) know what you think. Nick
Nicholas
S. Thompson Emeritus
Professor of Psychology and Ethology, Clark
University ([hidden email]) ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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